Remove deprecated methods which were marked for removal in Ktlint 2.0, and resolve TOOD's
diff --git a/ktlint-api-consumer/src/test/kotlin/com/pinterest/ktlint/api/consumer/KtLintRuleEngineTest.kt b/ktlint-api-consumer/src/test/kotlin/com/pinterest/ktlint/api/consumer/KtLintRuleEngineTest.kt
index 6da08ae..ef20055 100644
--- a/ktlint-api-consumer/src/test/kotlin/com/pinterest/ktlint/api/consumer/KtLintRuleEngineTest.kt
+++ b/ktlint-api-consumer/src/test/kotlin/com/pinterest/ktlint/api/consumer/KtLintRuleEngineTest.kt
@@ -158,104 +158,6 @@
     }
 
     @Nested
-    inner class `Format (legacy) with KtLintRuleEngine` {
-        @Test
-        fun `Given a file that does not contain an error`(
-            @TempDir
-            tempDir: Path,
-        ) {
-            val filePath = "$tempDir/Code.kt"
-            FileWriter(filePath).use {
-                it.write(
-                    """
-                    fun bar() {
-                        // bar
-                        }
-                    """.trimIndent(),
-                )
-            }
-
-            val lintErrors = mutableListOf<LintError>()
-            val actual =
-                @Suppress("DEPRECATION")
-                ktLintRuleEngine.format(
-                    code = Code.fromFile(File(filePath)),
-                ) { lintError, _ -> lintErrors.add(lintError) }
-
-            assertThat(lintErrors).containsExactlyInAnyOrder(
-                LintError(2, 5, RULE_WITH_AUTOCORRECT_APPROVE_HANDLER, "Bar comment with autocorrect approve handler", true),
-                LintError(3, 1, INDENTATION_RULE_ID, "Unexpected indentation (4) (should be 0)", true),
-            )
-            assertThat(actual).isEqualTo(
-                """
-                fun bar() {
-                    // BAR
-                }
-                """.trimIndent(),
-            )
-        }
-
-        @Test
-        fun `Given a kotlin code snippet that does contain an indentation error`() {
-            val lintErrors = mutableListOf<LintError>()
-            val actual =
-                @Suppress("DEPRECATION")
-                ktLintRuleEngine.format(
-                    code =
-                        Code.fromSnippet(
-                            """
-                            fun bar() {
-                                // bar
-                                }
-                            """.trimIndent(),
-                        ),
-                ) { lintError, _ -> lintErrors.add(lintError) }
-
-            assertThat(lintErrors).containsExactlyInAnyOrder(
-                LintError(2, 5, RULE_WITH_AUTOCORRECT_APPROVE_HANDLER, "Bar comment with autocorrect approve handler", true),
-                LintError(3, 1, INDENTATION_RULE_ID, "Unexpected indentation (4) (should be 0)", true),
-            )
-            assertThat(actual).isEqualTo(
-                """
-                fun bar() {
-                    // BAR
-                }
-                """.trimIndent(),
-            )
-        }
-
-        @Test
-        fun `Given a kotlin script code snippet that does contain an indentation error`() {
-            val lintErrors = mutableListOf<LintError>()
-            val actual =
-                @Suppress("DEPRECATION")
-                ktLintRuleEngine.format(
-                    code =
-                        Code.fromSnippet(
-                            """
-                            plugins {
-                                // bar
-                                }
-                            """.trimIndent(),
-                            script = true,
-                        ),
-                ) { lintError, _ -> lintErrors.add(lintError) }
-
-            assertThat(lintErrors).containsExactlyInAnyOrder(
-                LintError(2, 5, RULE_WITH_AUTOCORRECT_APPROVE_HANDLER, "Bar comment with autocorrect approve handler", true),
-                LintError(3, 1, INDENTATION_RULE_ID, "Unexpected indentation (4) (should be 0)", true),
-            )
-            assertThat(actual).isEqualTo(
-                """
-                plugins {
-                    // BAR
-                }
-                """.trimIndent(),
-            )
-        }
-    }
-
-    @Nested
     inner class `Format with KtLintRuleEngine` {
         @Nested
         inner class `Given a file that containing some errors` {
diff --git a/ktlint-cli-reporter-baseline/src/main/kotlin/com/pinterest/ktlint/cli/reporter/baseline/Baseline.kt b/ktlint-cli-reporter-baseline/src/main/kotlin/com/pinterest/ktlint/cli/reporter/baseline/Baseline.kt
index 939a3bc..e64b99f 100644
--- a/ktlint-cli-reporter-baseline/src/main/kotlin/com/pinterest/ktlint/cli/reporter/baseline/Baseline.kt
+++ b/ktlint-cli-reporter-baseline/src/main/kotlin/com/pinterest/ktlint/cli/reporter/baseline/Baseline.kt
@@ -71,16 +71,6 @@
 }
 
 /**
- * Loads the [Baseline] from the file located on [path]. Exceptions are swallowed and log message is written. On error, the baseline file is
- * deleted.
- */
-@Deprecated(
-    message = "Marked for removal in Ktlint 2.0",
-    replaceWith = ReplaceWith("loadBaseline(path, BaselineErrorHandling.LOG)"),
-)
-public fun loadBaseline(path: String): Baseline = loadBaseline(path, BaselineErrorHandling.LOG)
-
-/**
  * Loads the [Baseline] from the file located on [path]. In case the baseline file can not be loaded successfully, it will be deleted.
  */
 public fun loadBaseline(
@@ -121,8 +111,6 @@
             .toFile()
             .takeIf { it.exists() }
 
-    var ruleReferenceWithoutRuleSetIdPrefix = 0
-
     fun load(): Baseline {
         require(path.isNotBlank()) { "Path for loading baseline may not be blank or empty" }
 
@@ -133,15 +121,7 @@
                         path = path,
                         lintErrorsPerFile = baselineFile.inputStream().parseBaseline(),
                         status = VALID,
-                    ).also {
-                        if (ruleReferenceWithoutRuleSetIdPrefix > 0) {
-                            LOGGER.warn {
-                                "Baseline file '$path' contains $ruleReferenceWithoutRuleSetIdPrefix reference(s) to rule ids without " +
-                                    "a rule set id. For those references the rule set id 'standard' is assumed. It is advised to " +
-                                    "regenerate this baseline file."
-                            }
-                        }
-                    }
+                    )
                 } catch (e: IOException) {
                     throw BaselineLoaderException("Unable to parse baseline file: $path", e)
                 } catch (e: ParserConfigurationException) {
@@ -200,18 +180,7 @@
         KtlintCliError(
             line = getAttribute("line").toInt(),
             col = getAttribute("column").toInt(),
-            ruleId =
-                getAttribute("source")
-                    .let { ruleId ->
-                        // Ensure backwards compatibility with baseline files in which the rule set id for standard rules is not saved
-                        RuleId
-                            .prefixWithStandardRuleSetIdWhenMissing(ruleId)
-                            .also { prefixedRuleId ->
-                                if (prefixedRuleId != ruleId) {
-                                    ruleReferenceWithoutRuleSetIdPrefix++
-                                }
-                            }
-                    },
+            ruleId = getAttribute("source"),
             // Detail is not available in the baseline
             detail = "",
             status = BASELINE_IGNORED,
@@ -238,9 +207,7 @@
 public fun List<KtlintCliError>.containsLintError(ktlintCliError: KtlintCliError): Boolean = any { it.isSameAs(ktlintCliError) }
 
 private fun KtlintCliError.isSameAs(lintError: KtlintCliError) =
-    col == lintError.col &&
-        line == lintError.line &&
-        RuleId.prefixWithStandardRuleSetIdWhenMissing(ruleId) == RuleId.prefixWithStandardRuleSetIdWhenMissing(lintError.ruleId)
+    col == lintError.col && line == lintError.line && ruleId == lintError.ruleId
 
 /**
  * Checks if the list does not contain the given [KtlintCliError]. The [List.contains] function can not be used as [KtlintCliError.detail]
diff --git a/ktlint-cli-reporter-baseline/src/test/kotlin/com/pinterest/ktlint/cli/reporter/baseline/BaselineTest.kt b/ktlint-cli-reporter-baseline/src/test/kotlin/com/pinterest/ktlint/cli/reporter/baseline/BaselineTest.kt
index d95348f..681df37 100644
--- a/ktlint-cli-reporter-baseline/src/test/kotlin/com/pinterest/ktlint/cli/reporter/baseline/BaselineTest.kt
+++ b/ktlint-cli-reporter-baseline/src/test/kotlin/com/pinterest/ktlint/cli/reporter/baseline/BaselineTest.kt
@@ -121,21 +121,7 @@
     @Nested
     inner class `Baseline has invalid xml structure` {
         @Test
-        fun `Given that the baseline is loaded with classic loader then the log contains an error message`(
-            @TempDir
-            tempDir: Path,
-        ) {
-            val path = "baseline-invalid.xml".copyResourceToFileIn(tempDir)
-
-            val logCaptor = LogCaptor.forClass(Baseline::class.java)
-
-            loadBaseline(path)
-
-            assertThat(logCaptor.errorLogs).contains("Unable to parse baseline file: $path")
-        }
-
-        @Test
-        fun `Given that the baseline is loaded with new loader then an exception is thrown on error`(
+        fun `Given that the baseline is loaded with BaselineErrorHandling EXCEPTION then on error an exception is thrown`(
             @TempDir
             tempDir: Path,
         ) {
@@ -150,7 +136,7 @@
         }
 
         @Test
-        fun `Given that the baseline is loaded with new loader then the log message is printed and no exception is thrown`(
+        fun `Given that the baseline is loaded with BaselineErrorHandling LOG then on error a the log message is printed and no exception is thrown`(
             @TempDir
             tempDir: Path,
         ) {
@@ -158,7 +144,7 @@
 
             val logCaptor = LogCaptor.forClass(Baseline::class.java)
 
-            loadBaseline(path)
+            loadBaseline(path, BaselineErrorHandling.LOG)
 
             assertThat(logCaptor.errorLogs).contains("Unable to parse baseline file: $path")
         }
diff --git a/ktlint-cli/src/main/kotlin/com/pinterest/ktlint/cli/internal/KtlintCommandLine.kt b/ktlint-cli/src/main/kotlin/com/pinterest/ktlint/cli/internal/KtlintCommandLine.kt
index fb0325a..a8763fd 100644
--- a/ktlint-cli/src/main/kotlin/com/pinterest/ktlint/cli/internal/KtlintCommandLine.kt
+++ b/ktlint-cli/src/main/kotlin/com/pinterest/ktlint/cli/internal/KtlintCommandLine.kt
Binary files differ
diff --git a/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/SimpleCLITest.kt b/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/SimpleCLITest.kt
index d13e87b..4fd178f 100644
--- a/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/SimpleCLITest.kt
+++ b/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/SimpleCLITest.kt
@@ -505,24 +505,6 @@
     }
 
     @Test
-    fun `Given that the deprecated parameter --code-style is specified, then return an error`(
-        @TempDir
-        tempDir: Path,
-    ) {
-        CommandLineTestRunner(tempDir)
-            .run(
-                testProjectName = "too-many-empty-lines",
-                arguments = listOf("--code-style=android_studio"),
-                expectExitCodeLoggedWhenKtlintIsFinished = false,
-            ) {
-                assertThat(errorOutput).containsLineMatching(
-                    "Parameter '--code-style' is no longer valid. The code style should be defined as '.editorconfig' property " +
-                        "'ktlint_code_style='",
-                )
-            }
-    }
-
-    @Test
     fun `Issue 3096 - Given some code containing unicode characters, the code is provided via stdin then write the formatted code to stdout in UTF-8 to preserve the unicode characters`(
         @TempDir
         tempDir: Path,
diff --git a/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/api/BaselineCLITest.kt b/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/api/BaselineCLITest.kt
index 7e30579..a905db5 100644
--- a/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/api/BaselineCLITest.kt
+++ b/ktlint-cli/src/test/kotlin/com/pinterest/ktlint/cli/api/BaselineCLITest.kt
@@ -61,12 +61,6 @@
                                 .doesNotContainLineMatching(Regex(".*/$projectName/TestBaselineFile.kt.test:1:24: Unnecessary block.*"))
                                 .doesNotContainLineMatching(
                                     Regex(".*/$projectName/some/path/to/TestBaselineFile.kt.test:1:24: Unnecessary block.*"),
-                                ).containsLineMatching(
-                                    Regex(
-                                        ".*Baseline file '$baselinePath' contains 4 reference\\(s\\) to rule ids without a rule set id. " +
-                                            "For those references the rule set id 'standard' is assumed. It is advised to regenerate " +
-                                            "this baseline file.*",
-                                    ),
                                 ).doesNotContainLineMatching(
                                     Regex(
                                         ".*Format was not able to resolve all violations which \\(theoretically\\) can be autocorrected in file.*",
@@ -100,12 +94,6 @@
                                 .doesNotContainLineMatching(Regex(".*/$projectName/TestBaselineFile.kt.test:1:24: Unnecessary block.*"))
                                 .doesNotContainLineMatching(
                                     Regex(".*/$projectName/some/path/to/TestBaselineFile.kt.test:1:24: Unnecessary block.*"),
-                                ).containsLineMatching(
-                                    Regex(
-                                        ".*Baseline file '$baselinePath' contains 4 reference\\(s\\) to rule ids without a rule set id. " +
-                                            "For those references the rule set id 'standard' is assumed. It is advised to regenerate " +
-                                            "this baseline file.*",
-                                    ),
                                 )
                         }.assertAll()
                 }
@@ -133,14 +121,6 @@
                             assertThat(normalOutput)
                                 .doesNotContainLineMatching(Regex("^TestBaselineFile.kt.test:1:24: Unnecessary block.*"))
                                 .doesNotContainLineMatching(Regex("^some/path/to/TestBaselineFile.kt.test:1:24: Unnecessary block.*"))
-                                .containsLineMatching(
-                                    Regex(
-                                        // Escape "\" in baseline path for Windows
-                                        ".*Baseline file '${baselinePath.replace("\\", "\\\\")}' contains 4 " +
-                                            "reference\\(s\\) to rule ids without a rule set id. For those references the rule set id " +
-                                            "'standard' is assumed. It is advised to regenerate this baseline file.*",
-                                    ),
-                                )
                         }.assertAll()
                 }
         }
@@ -177,12 +157,6 @@
                                     ".*/$projectName/some/path/to/TestBaselineExtraErrorFile.kt.test:1:1: Replace the block comment with " +
                                         "an EOL comment.*",
                                 ),
-                            ).containsLineMatching(
-                                Regex(
-                                    ".*Baseline file '$baselinePath' contains 4 reference\\(s\\) to rule ids without a rule set id. For " +
-                                        "those references the rule set id 'standard' is assumed. It is advised to regenerate this " +
-                                        "baseline file.*",
-                                ),
                             )
                     }.assertAll()
             }
diff --git a/ktlint-cli/src/test/resources/cli/baseline/config/test-baseline.xml b/ktlint-cli/src/test/resources/cli/baseline/config/test-baseline.xml
index ec2b8a0..7d2009c 100644
--- a/ktlint-cli/src/test/resources/cli/baseline/config/test-baseline.xml
+++ b/ktlint-cli/src/test/resources/cli/baseline/config/test-baseline.xml
@@ -1,15 +1,15 @@
 <?xml version="1.0" encoding="utf-8"?>
 <baseline version="1.0">
     <file name="TestBaselineExtraErrorFile.kt.test">
-        <error line="2" column="34" source="no-empty-class-body" />
+        <error line="2" column="34" source="standard:no-empty-class-body" />
     </file>
     <file name="TestBaselineFile.kt.test">
-        <error line="1" column="24" source="no-empty-class-body" />
+        <error line="1" column="24" source="standard:no-empty-class-body" />
     </file>
     <file name="some/path/to/TestBaselineExtraErrorFile.kt.test">
-        <error line="2" column="34" source="no-empty-class-body" />
+        <error line="2" column="34" source="standard:no-empty-class-body" />
     </file>
     <file name="some/path/to/TestBaselineFile.kt.test">
-        <error line="1" column="24" source="no-empty-class-body" />
+        <error line="1" column="24" source="standard:no-empty-class-body" />
     </file>
 </baseline>
diff --git a/ktlint-cli/src/test/resources/cli/baseline/test-baseline.xml b/ktlint-cli/src/test/resources/cli/baseline/test-baseline.xml
index ec2b8a0..7d2009c 100644
--- a/ktlint-cli/src/test/resources/cli/baseline/test-baseline.xml
+++ b/ktlint-cli/src/test/resources/cli/baseline/test-baseline.xml
@@ -1,15 +1,15 @@
 <?xml version="1.0" encoding="utf-8"?>
 <baseline version="1.0">
     <file name="TestBaselineExtraErrorFile.kt.test">
-        <error line="2" column="34" source="no-empty-class-body" />
+        <error line="2" column="34" source="standard:no-empty-class-body" />
     </file>
     <file name="TestBaselineFile.kt.test">
-        <error line="1" column="24" source="no-empty-class-body" />
+        <error line="1" column="24" source="standard:no-empty-class-body" />
     </file>
     <file name="some/path/to/TestBaselineExtraErrorFile.kt.test">
-        <error line="2" column="34" source="no-empty-class-body" />
+        <error line="2" column="34" source="standard:no-empty-class-body" />
     </file>
     <file name="some/path/to/TestBaselineFile.kt.test">
-        <error line="1" column="24" source="no-empty-class-body" />
+        <error line="1" column="24" source="standard:no-empty-class-body" />
     </file>
 </baseline>
diff --git a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt
index e22a160..48f621d 100644
--- a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt
+++ b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt
@@ -9,9 +9,6 @@
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.STRING_TEMPLATE
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_ARGUMENT
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_ARGUMENT_LIST
-import com.pinterest.ktlint.rule.engine.core.api.ElementType.VAL_KEYWORD
-import com.pinterest.ktlint.rule.engine.core.api.ElementType.VARARG_KEYWORD
-import com.pinterest.ktlint.rule.engine.core.api.ElementType.VAR_KEYWORD
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.WHITE_SPACE
 import org.jetbrains.kotlin.KtNodeType
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -25,43 +22,13 @@
 import org.jetbrains.kotlin.lexer.KtToken
 import org.jetbrains.kotlin.psi.KtAnnotated
 import org.jetbrains.kotlin.psi.KtElement
-import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtFile
-import org.jetbrains.kotlin.psi.KtLoopExpression
 import org.jetbrains.kotlin.psi.psiUtil.leaves
 import org.jetbrains.kotlin.psi.psiUtil.parents
 import org.jetbrains.kotlin.psi.stubs.elements.KtFileElementType
 import org.jetbrains.kotlin.psi.stubs.elements.KtStubElementType
 import org.jetbrains.kotlin.psi.stubs.elements.KtTokenSets
 import org.jetbrains.kotlin.util.prefixIfNot
-import org.jetbrains.kotlin.utils.addToStdlib.applyIf
-import kotlin.contracts.ExperimentalContracts
-import kotlin.contracts.contract
-import kotlin.reflect.KClass
-
-/**
- * In Ktlint 2.0 all ASTNode extensions functions will be replaced with property access where applicable. For now (ktlint 1.x) those
- * property accessors are prefixed with `_` to avoid name clashes with the functions. You are encouraged to replace the deprecated
- * functions with the accessors prefixed with `_` with use of the IntelliJ IDEA functionality. In Ktlint 2.0 the functions will be removed,
- * and the prefix `_` will be removed from the accessors.
- */
-
-@Deprecated(
-    "Marked for removal in KtLint 2.0. Replace calls to 'nextLeaf()', 'nextLeaf(false)', and 'nextLeaf(false, false)' with " +
-        "property accessor 'nextLeaf'. For any situation, use 'nextLeaf((ASTNode) -> Boolean)'.",
-)
-public fun ASTNode.nextLeaf(
-    includeEmpty: Boolean = false,
-    skipSubtree: Boolean = false,
-): ASTNode? {
-    var n = if (skipSubtree) lastChildLeafOrSelf20.nextLeafAny else this.nextLeafAny
-    if (!includeEmpty) {
-        while (n != null && n.textLength == 0) {
-            n = n.nextLeafAny
-        }
-    }
-    return n
-}
 
 /**
  * The next leaf after [ASTNode], or null when no such leaf exists.
@@ -99,20 +66,12 @@
     }
 
 private val ASTNode.nextLeafStrict
-    get(): ASTNode? = nextSibling20?.firstChildLeafOrSelf20 ?: parent?.nextLeafStrict
-
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("firstChildLeafOrSelf20"),
-)
-public fun ASTNode.firstChildLeafOrSelf(): ASTNode = firstChildLeafOrSelf20
+    get(): ASTNode? = nextSibling?.firstChildLeafOrSelf ?: parent?.nextLeafStrict
 
 /**
  * The first child leaf in [ASTNode], or [ASTNode] when it does not contain any children.
  */
-public val ASTNode.firstChildLeafOrSelf20: ASTNode
+public val ASTNode.firstChildLeafOrSelf: ASTNode
     get(): ASTNode {
         var node = this
         while (node.firstChildNode != null) {
@@ -121,21 +80,6 @@
         return node
     }
 
-@Deprecated(
-    "Marked for removal in KtLint 2.0. Replace calls to 'prevLeaf()', and 'prevLeaf(false)' with property accessor 'prevLeaf'. For any " +
-        "situation, use 'prevLeaf((ASTNode) -> Boolean)'.",
-    replaceWith = ReplaceWith("prevLeaf"),
-)
-public fun ASTNode.prevLeaf(includeEmpty: Boolean = false): ASTNode? {
-    var n = this.prevLeafAny
-    if (!includeEmpty) {
-        while (n != null && n.textLength == 0) {
-            n = n.prevLeafAny
-        }
-    }
-    return n
-}
-
 /**
  * The previous leaf before [ASTNode], or null when no such leaf exists.
  */
@@ -160,20 +104,12 @@
 }
 
 private val ASTNode.prevLeafAny
-    get(): ASTNode? = prevSibling20?.lastChildLeafOrSelf20 ?: parent?.prevLeafAny
-
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("lastChildLeafOrSelf20"),
-)
-public fun ASTNode.lastChildLeafOrSelf(): ASTNode = lastChildLeafOrSelf20
+    get(): ASTNode? = prevSibling?.lastChildLeafOrSelf ?: parent?.prevLeafAny
 
 /**
  * The last child leaf in [ASTNode], or [ASTNode] when it does not contain any children.
  */
-public val ASTNode.lastChildLeafOrSelf20: ASTNode
+public val ASTNode.lastChildLeafOrSelf: ASTNode
     get(): ASTNode {
         var node = this
         while (node.lastChildNode != null) {
@@ -186,19 +122,7 @@
  *  `true` when [ASTNode] is not a whitespace element, and is not part of a comment.
  */
 public val ASTNode.isCode: Boolean
-    get(): Boolean = !isWhiteSpace20 && !isPartOfComment20
-
-@Deprecated(
-    "Marked for removal in KtLint 2.0. Replace calls to 'prevCodeLeaf()', and 'prevCodeLeaf(false)' with property accessor " +
-        "'prevCodeLeaf'. For any other situation, use 'prevCodeLeaf((ASTNode) -> Boolean)'.",
-)
-public fun ASTNode.prevCodeLeaf(includeEmpty: Boolean = false): ASTNode? {
-    var n = prevLeaf(includeEmpty)
-    while (n != null && !n.isCode) {
-        n = n.prevLeaf(includeEmpty)
-    }
-    return n
-}
+    get(): Boolean = !isWhiteSpace && !isPartOfComment
 
 /**
  * The previous code leaf before [ASTNode], or null when no such leaf exists.
@@ -212,21 +136,6 @@
         return node
     }
 
-@Deprecated(
-    "Marked for removal in KtLint 2.0. Replace calls to 'nextCodeLeaf()', 'nextCodeLeaf(false)', and 'nextCodeLeaf(false, false)' with " +
-        "property accessor 'nextCodeLeaf'. For any other situation, use 'nextCodeLeaf((ASTNode) -> Boolean)'.",
-)
-public fun ASTNode.nextCodeLeaf(
-    includeEmpty: Boolean = false,
-    skipSubtree: Boolean = false,
-): ASTNode? {
-    var n = nextLeaf
-    while (n != null && !n.isCode) {
-        n = n.nextLeaf
-    }
-    return n
-}
-
 /**
  * The next code leaf after [ASTNode], or null when no such leaf exists.
  */
@@ -239,18 +148,10 @@
         return node
     }
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("prevCodeSibling20"),
-)
-public fun ASTNode.prevCodeSibling(): ASTNode? = prevCodeSibling20
-
 /**
  * The previous code sibling of [ASTNode], or null when no such sibling exists.
  */
-public val ASTNode.prevCodeSibling20: ASTNode?
+public val ASTNode.prevCodeSibling: ASTNode?
     get(): ASTNode? = prevSibling { it.isCode }
 
 /**
@@ -267,33 +168,16 @@
     return null
 }
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("prevSibling20"),
-)
-public fun ASTNode.prevSibling(): ASTNode? = prevSibling20
-
 /**
  * The previous sibling of [ASTNode], or null when no such sibling exists.
  */
-public inline val ASTNode.prevSibling20: ASTNode?
+public inline val ASTNode.prevSibling: ASTNode?
     get(): ASTNode? = treePrev
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("nextCodeSibling20"),
-)
-// TODO: In Ktlint 2.0 replace with accessor without temporary suffix "20"
-public fun ASTNode.nextCodeSibling(): ASTNode? = nextCodeSibling20
-
 /**
  * The next code sibling of [ASTNode], or null when no such sibling exists.
  */
-public val ASTNode.nextCodeSibling20: ASTNode?
+public val ASTNode.nextCodeSibling: ASTNode?
     get(): ASTNode? = nextSibling { it.isCode }
 
 /**
@@ -310,18 +194,10 @@
     return null
 }
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("nextSibling20"),
-)
-public fun ASTNode.nextSibling(): ASTNode? = nextSibling20
-
 /**
  * The next sibling of [ASTNode], or null when no such sibling exists.
  */
-public inline val ASTNode.nextSibling20: ASTNode?
+public inline val ASTNode.nextSibling: ASTNode?
     get(): ASTNode? = treeNext
 
 /**
@@ -331,33 +207,6 @@
     get(): ASTNode? = treeParent
 
 /**
- * @param elementType [ElementType].*
- */
-@Deprecated(
-    "Marked for removal in Ktlint 2.0",
-    replaceWith = ReplaceWith("findParentByType(elementType)"),
-)
-public fun ASTNode.parent(
-    elementType: IElementType,
-    strict: Boolean = true,
-): ASTNode? {
-    var n: ASTNode? = if (strict) this.parent else this
-    while (n != null) {
-        if (n.elementType == elementType) {
-            return n
-        }
-        n = n.parent
-    }
-    return null
-}
-
-@Deprecated(
-    message = "Marked for removal in Ktlint 2.0",
-    replaceWith = ReplaceWith("findParentByType(elementType)"),
-)
-public fun ASTNode.parent(elementType: IElementType): ASTNode? = findParentByType(elementType)
-
-/**
  * Find the first parent from [ASTNode] with [elementType].
  */
 public fun ASTNode.findParentByType(elementType: IElementType): ASTNode? {
@@ -371,21 +220,6 @@
     return null
 }
 
-@Deprecated("Marked for removal in Ktlint 2.0")
-public fun ASTNode.parent(
-    strict: Boolean = true,
-    predicate: (ASTNode) -> Boolean,
-): ASTNode? {
-    var n: ASTNode? = if (strict) this.parent else this
-    while (n != null) {
-        if (predicate(n)) {
-            return n
-        }
-        n = n.parent
-    }
-    return null
-}
-
 /**
  * Find the first parent from [ASTNode] matching [predicate].
  */
@@ -407,176 +241,64 @@
  */
 public fun ASTNode.isPartOf(elementType: IElementType): Boolean = this.elementType == elementType || findParentByType(elementType) != null
 
-@Deprecated(
-    "Marked for removal in Ktlint 2.x. Replace with ASTNode.isPartOf(elementType: IElementType) or ASTNode.isPartOf(tokenSet: TokenSet). " +
-        "This method might cause performance issues, see https://github.com/pinterest/ktlint/pull/2901",
-    replaceWith = ReplaceWith("this.isPartOf(elementTypeOrTokenSet)"),
-)
-public fun ASTNode.isPartOf(klass: KClass<out PsiElement>): Boolean {
-    var node: ASTNode? = this
-    while (node != null) {
-        if (klass.java.isInstance(node.psi)) {
-            return true
-        }
-        node = node.parent
-    }
-    return false
-}
-
-@Deprecated("Marked for removal in KtLint 2.0")
-public fun ASTNode.isPartOfCompositeElementOfType(iElementType: IElementType): Boolean =
-    iElementType == findCompositeParentElementOfType(iElementType)?.elementType
-
-@Deprecated("Marked for removal in KtLint 2.0")
-public fun ASTNode.findCompositeParentElementOfType(iElementType: IElementType): ASTNode? =
-    parent { it.elementType == iElementType || it !is CompositeElement }
-
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isPartOfString20"),
-)
-public fun ASTNode.isPartOfString(): Boolean = isPartOfString20
-
 /**
  * `true` when [ASTNode] is part of a string template
  */
-public val ASTNode.isPartOfString20: Boolean
+public val ASTNode.isPartOfString: Boolean
     get(): Boolean = findParentByType(STRING_TEMPLATE) != null
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isWhiteSpace20"),
-)
-@OptIn(ExperimentalContracts::class)
-public fun ASTNode?.isWhiteSpace(): Boolean {
-    contract {
-        returns(true) implies (this@isWhiteSpace != null)
-    }
-    return isWhiteSpace20
-}
-
 /**
  * `true` when [ASTNode] is a whitespace element
  */
-public val ASTNode?.isWhiteSpace20: Boolean
+public val ASTNode?.isWhiteSpace: Boolean
     get() = this != null && elementType == WHITE_SPACE
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isWhiteSpaceWithNewline20"),
-)
-public fun ASTNode?.isWhiteSpaceWithNewline(): Boolean = isWhiteSpaceWithNewline20
-
 /**
  * `true` when [ASTNode] is a whitespace element that contains a newline
  */
-public val ASTNode?.isWhiteSpaceWithNewline20: Boolean
-    get(): Boolean = this != null && isWhiteSpace20 && textContains('\n')
-
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isWhiteSpaceWithoutNewline20"),
-)
-public fun ASTNode?.isWhiteSpaceWithoutNewline(): Boolean = isWhiteSpaceWithoutNewline20
+public val ASTNode?.isWhiteSpaceWithNewline: Boolean
+    get(): Boolean = this != null && isWhiteSpace && textContains('\n')
 
 /**
  * `true` when [ASTNode] is a whitespace element not containing a newline
  */
-public val ASTNode?.isWhiteSpaceWithoutNewline20: Boolean
-    get(): Boolean = this != null && isWhiteSpace20 && !textContains('\n')
+public val ASTNode?.isWhiteSpaceWithoutNewline: Boolean
+    get(): Boolean = this != null && isWhiteSpace && !textContains('\n')
 
 /**
  * `true` when [ASTNode] is null, or when [ASTNode] is a whitespace element not containing a newline
  */
 public val ASTNode?.isWhiteSpaceWithoutNewlineOrNull: Boolean
-    get(): Boolean = this == null || isWhiteSpaceWithoutNewline20
-
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isRoot20"),
-)
-public fun ASTNode.isRoot(): Boolean = isRoot20
+    get(): Boolean = this == null || isWhiteSpaceWithoutNewline
 
 /**
  * `true` when [ASTNode] is the root (e.g. FILE) element type
  */
-public val ASTNode.isRoot20: Boolean
+public val ASTNode.isRoot: Boolean
     get(): Boolean = elementType == FILE
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isLeaf20"),
-)
-public fun ASTNode.isLeaf(): Boolean = isLeaf20
-
 /**
  * `true` when [ASTNode] is a leaf element type
  */
-public val ASTNode.isLeaf20: Boolean
+public val ASTNode.isLeaf: Boolean
     get(): Boolean = firstChildNode == null
 
 /**
- * Check if the given [ASTNode] is a code leaf. E.g. it must be a leaf and may not be a whitespace or be part of a
- * comment.
- */
-@Deprecated("Marked for removal in Ktlint 2.0. Use `isLeaf20 && isCode` instead")
-public fun ASTNode.isCodeLeaf(): Boolean = isLeaf20 && isCode
-
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isPartOfComment20"),
-)
-public fun ASTNode.isPartOfComment(): Boolean = isPartOfComment20
-
-/**
  * `true` when [ASTNode] is part of a comment
  */
-public val ASTNode.isPartOfComment20: Boolean
+public val ASTNode.isPartOfComment: Boolean
     get(): Boolean = isPartOf(TokenSets.COMMENTS)
 
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("children20"),
-)
-public fun ASTNode.children(): Sequence<ASTNode> = children20
-
 /**
  * A sequence of the children of [ASTNode]
  */
-public val ASTNode.children20: Sequence<ASTNode>
-    get(): Sequence<ASTNode> = generateSequence(firstChildNode) { node -> node.nextSibling20 }
-
-@Deprecated("Marked for removal in Ktlint 2.0")
-public fun ASTNode.recursiveChildren(includeSelf: Boolean = false): Sequence<ASTNode> = recursiveChildrenInternal(includeSelf)
-
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("recursiveChildren20"),
-)
-public fun ASTNode.recursiveChildren(): Sequence<ASTNode> = recursiveChildren20
+public val ASTNode.children: Sequence<ASTNode>
+    get(): Sequence<ASTNode> = generateSequence(firstChildNode) { node -> node.nextSibling }
 
 /**
  * A sequence of the children of [ASTNode] recursively iterated
  */
-public val ASTNode.recursiveChildren20: Sequence<ASTNode>
+public val ASTNode.recursiveChildren: Sequence<ASTNode>
     get(): Sequence<ASTNode> = recursiveChildrenInternal(false)
 
 private fun ASTNode.recursiveChildrenInternal(includeSelf: Boolean = false): Sequence<ASTNode> =
@@ -584,7 +306,7 @@
         if (includeSelf) {
             yield(this@recursiveChildrenInternal)
         }
-        this@recursiveChildrenInternal.children20.forEach { yieldAll(it.recursiveChildrenInternal(includeSelf = true)) }
+        this@recursiveChildrenInternal.children.forEach { yieldAll(it.recursiveChildrenInternal(includeSelf = true)) }
     }
 
 /**
@@ -593,13 +315,13 @@
  * added after the previous leaf node.
  */
 public fun ASTNode.upsertWhitespaceBeforeMe(text: String) {
-    if (isLeaf20) {
-        if (isWhiteSpace20) {
+    if (isLeaf) {
+        if (isWhiteSpace) {
             return replaceTextWith(text)
         }
-        val previous = prevSibling20 ?: this.prevLeaf
+        val previous = prevSibling ?: this.prevLeaf
         when {
-            previous != null && previous.isWhiteSpace20 -> {
+            previous != null && previous.isWhiteSpace -> {
                 previous.replaceTextWith(text)
             }
 
@@ -615,7 +337,7 @@
             }
         }
     } else {
-        when (val prevSibling = prevSibling20) {
+        when (val prevSibling = prevSibling) {
             null -> {
                 // Never insert a whitespace element as first child node in a composite node. Instead, upsert just before the composite node
                 parent?.upsertWhitespaceBeforeMe(text)
@@ -650,13 +372,13 @@
  * added after the last child leaf.
  */
 public fun ASTNode.upsertWhitespaceAfterMe(text: String) {
-    if (isLeaf20) {
-        if (isWhiteSpace20) {
+    if (isLeaf) {
+        if (isWhiteSpace) {
             return replaceTextWith(text)
         }
-        val next = nextSibling20 ?: nextLeaf
+        val next = nextSibling ?: nextLeaf
         when {
-            next != null && next.isWhiteSpace20 -> {
+            next != null && next.isWhiteSpace -> {
                 next.replaceTextWith(text)
             }
 
@@ -672,7 +394,7 @@
             }
         }
     } else {
-        when (val nextSibling = nextSibling20) {
+        when (val nextSibling = nextSibling) {
             null -> {
                 // Never insert a whitespace element as last child node in a composite node. Instead, upsert just after the composite node
                 parent?.upsertWhitespaceAfterMe(text)
@@ -700,7 +422,7 @@
         var leaf = prevLeaf
         var offsetToTheLeft = 0
         while (leaf != null) {
-            if (leaf.isWhiteSpaceWithNewline20) {
+            if (leaf.isWhiteSpaceWithNewline) {
                 offsetToTheLeft += leaf.textLength - 1 - leaf.text.lastIndexOf('\n')
                 break
             }
@@ -711,26 +433,9 @@
     }
 
 /**
- * Get the current indentation of the line containing the [ASTNode]. By default, this indentation starts with a newline (\n) character.
- */
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "one of the temporary property accessor. Calls to `indent()` or `indent(true)` should be replaced with `indent20()`. Calls " +
-        "to `indent(false)` should be replaced with `indentWithoutNewlinePrefix()` In 2.0 the temporary accessors will be replaced " +
-        "the final property accessors.",
-    replaceWith = ReplaceWith("indent20 or indentWithoutNewlinePrefix"),
-)
-public fun ASTNode.indent(includeNewline: Boolean = true): String =
-    if (includeNewline) {
-        indent20
-    } else {
-        indentWithoutNewlinePrefix
-    }
-
-/**
  * The indentation of [ASTNode] including the newline prefix
  */
-public val ASTNode.indent20: String
+public val ASTNode.indent: String
     get(): String = indentInternal().prefixIfNot("\n")
 
 /**
@@ -744,30 +449,12 @@
  */
 private fun ASTNode.indentInternal(): String =
     leaves(forward = false)
-        .firstOrNull { it.isWhiteSpaceWithNewline20 }
+        .firstOrNull { it.isWhiteSpaceWithNewline }
         ?.text
         ?.substringAfterLast('\n')
         .orEmpty() // Fallback if node is not preceded by any newline character
 
 /**
- *  Print content of a node and the element type of the node, its parent and its direct children. Utility is meant to
- *  be used during development only. Please do not remove.
- */
-@Suppress("unused")
-@Deprecated("Marked for removal in Ktlint 2.0. Use PsiViewer plugin instead")
-public fun ASTNode.logStructure(): ASTNode =
-    also {
-        println("Processing ${text.replaceTabAndNewline()} : Type $elementType with parent ${parent?.elementType} ")
-        children20
-            .toList()
-            .map {
-                println("  ${it.text.replaceTabAndNewline()} : Type ${it.elementType}")
-            }
-    }
-
-private fun String.replaceTabAndNewline(): String = replace("\t", "\\t").replace("\n", "\\n")
-
-/**
  * Verifies that a leaf containing a newline exist in the closed range [from] - [to]. Also, returns true in case any of
  * the boundary nodes [from] or [to] contains a newline.
  */
@@ -808,7 +495,7 @@
 ): Sequence<ASTNode> =
     from
         .leaves()
-        .takeWhile { it != to && it != to.lastChildLeafOrSelf20 }
+        .takeWhile { it != to && it != to.lastChildLeafOrSelf }
 
 /**
  * Creates a sequence of leaf nodes in the closed range [from] - [to]. This means that the boundary nodes are included from the range in
@@ -822,32 +509,14 @@
 ): Sequence<ASTNode> {
     val stopAtLeaf =
         to
-            .lastChildLeafOrSelf20
+            .lastChildLeafOrSelf
             .nextLeaf
     return from
-        .firstChildLeafOrSelf20
+        .firstChildLeafOrSelf
         .leavesForwardsIncludingSelf
         .takeWhile { it != stopAtLeaf }
 }
 
-@Deprecated("Marked for removal in Ktlint 2.0")
-public fun ASTNode.isValOrVarKeyword(): Boolean = elementType == VAL_KEYWORD || elementType == VAR_KEYWORD || elementType == VARARG_KEYWORD
-
-/**
- * Creates a sequences of leaves including the [ASTNode] in case it is a [LeafElement] itself. By default, the leaves are traversed in
- * forward order. Setting [forward] to `false` changes this to traversal in backward direction.
- */
-@Deprecated("Marked for removal in Ktlint 2.0. Use `leavesForwardsIncludingSelf` or `leavesBackwardsIncludingSelf` instead")
-public fun ASTNode.leavesIncludingSelf(forward: Boolean = true): Sequence<ASTNode> {
-    val sequence =
-        if (isLeaf20) {
-            sequenceOf(this)
-        } else {
-            emptySequence()
-        }
-    return sequence.plus(leaves(forward))
-}
-
 /**
  * Creates a forward sequence of leaves including the [ASTNode] in case it is a [LeafElement] itself. Otherwise, an empty sequence is
  * returned.
@@ -865,7 +534,7 @@
 private val ASTNode.sequenceOfLeafOrEmpty
     get(): Sequence<ASTNode> {
         val sequence =
-            if (isLeaf20) {
+            if (isLeaf) {
                 sequenceOf(this)
             } else {
                 emptySequence()
@@ -874,21 +543,9 @@
     }
 
 /**
- * Get all leaves on the same line as the given node including the whitespace indentation. Note that the whitespace indentation may start
- * with zero or more newline characters.
- */
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("leavesOnLine20"),
-)
-public fun ASTNode.leavesOnLine(): Sequence<ASTNode> = leavesOnLine20
-
-/**
  * A sequence of all leaves on the same line at which the [ASTNode] starts
  */
-public val ASTNode.leavesOnLine20: Sequence<ASTNode>
+public val ASTNode.leavesOnLine: Sequence<ASTNode>
     get(): Sequence<ASTNode> {
         val takeAll = lastLeafOnLineOrNull == null
         return firstLeafOnLineOrSelf
@@ -897,74 +554,24 @@
     }
 
 /**
- * Get all leaves on the same line as the given node including the whitespace indentation. Note that the whitespace indentation may start
- * with zero or more newline characters.
- */
-@Deprecated(
-    "Marked for removal in Ktlint 2.0. Use 'leavesOnLine20.dropTrailingEolComment()' to get all leaves on the line without the " +
-        "trailing EOL comment",
-)
-public fun ASTNode.leavesOnLine(excludeEolComment: Boolean): Sequence<ASTNode> =
-    leavesOnLine20.applyIf(excludeEolComment) { dropTrailingEolComment() }
-
-/**
  * Take all nodes preceding the whitespace before the EOL comment
  */
 public fun Sequence<ASTNode>.dropTrailingEolComment(): Sequence<ASTNode> =
     takeWhile {
-        !(it.isWhiteSpaceWithoutNewline20 && it.nextLeaf?.elementType == EOL_COMMENT) &&
+        !(it.isWhiteSpaceWithoutNewline && it.nextLeaf?.elementType == EOL_COMMENT) &&
             // But if EOL-comment not preceded by whitespace than take all nodes before the EOL comment
             it.elementType != EOL_COMMENT
     }
 
 internal val ASTNode.firstLeafOnLineOrSelf
     get() =
-        prevLeaf { (it.textContains('\n') && !it.isPartOfComment20) || it.prevLeaf == null }
+        prevLeaf { (it.textContains('\n') && !it.isPartOfComment) || it.prevLeaf == null }
             ?: this
 
 internal val ASTNode.lastLeafOnLineOrNull
     get() = nextLeaf { it.textContains('\n') }?.prevLeaf
 
 /**
- * Get the total length of all leaves on the same line as the given node including the whitespace indentation but excluding all leading
- * newline characters in the whitespace indentation. Note that EOL-comments are included in the line length calculation. This can lead to
- * rules modifying the code before the EOL-comment in case the EOL-comment causes the max_line_length to be exceeded. It should be
- * preferred to prevent this by excluding the EOL-comment from the calculation (use [lineLength]), and let max-line-length rule report the
- * violation.
- */
-@Deprecated(
-    message =
-        "Marked for removal in Ktlint 2.x. Rules should not modify code in case the EOL comment causes the max_line_length to be exceeded.",
-    replaceWith = ReplaceWith("lineLength(excludeEolComment = false)"),
-)
-public fun ASTNode.lineLengthWithoutNewlinePrefix(): Int = leavesOnLine20.lineLength
-
-/**
- * Get the total length of all leaves on the same line as the given node including the whitespace indentation but excluding all leading
- * newline characters in the whitespace indentation. Use [excludeEolComment] to exclude the EOL-comment (and preceding whitespace) from this
- * calculation. Note that rules should not modify code in case the EOL comment causes the max_line_length to be exceeded. Instead, let the
- * max-line-length rule report this violation so that the developer can choose whether the comment can be shortened or that it can be placed
- * on a separate line.
- */
-@Deprecated(
-    "Marked for removal in Ktlint 2.0. Use `leavesOnLine20.dropTrailingEolComment().lineLength` instead to get the length of the line " +
-        "without the trailing EOL comment.`",
-)
-public fun ASTNode.lineLength(excludeEolComment: Boolean = false): Int = leavesOnLine(excludeEolComment).lineLength
-
-/**
- * Get the total length of all leaves in the sequence including the whitespace indentation but excluding all leading newline characters in
- * the whitespace indentation. The first leaf node in the sequence must be a white space starting with at least one newline.
- */
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("lineLength"),
-)
-public fun Sequence<ASTNode>.lineLengthWithoutNewlinePrefix(): Int = lineLength
-
-/**
  * The length of the first non-empty line in the [Sequence] of [ASTNode]'s
  */
 public val Sequence<ASTNode>.lineLength: Int
@@ -1007,7 +614,7 @@
  */
 public fun ASTNode.hasModifier(iElementType: IElementType): Boolean =
     findChildByType(MODIFIER_LIST)
-        ?.children20
+        ?.children
         .orEmpty()
         .any { it.elementType == iElementType }
 
@@ -1028,40 +635,14 @@
 
 /**
  * Searches the receiver [ASTNode] recursively, returning the first child with type [elementType]. If none are found, returns `null`.
- * If [includeSelf] is `true`, includes the receiver in the search. The receiver would then be the first element searched, so it is
- * guaranteed to be returned if it has type [elementType].
- */
-@Deprecated("Marked for removal in KtLint 2.0")
-public fun ASTNode.findChildByTypeRecursively(
-    elementType: IElementType,
-    includeSelf: Boolean,
-): ASTNode? =
-    recursiveChildren(includeSelf).firstOrNull {
-        it.elementType ==
-            elementType
-    }
-
-/**
- * Searches the receiver [ASTNode] recursively, returning the first child with type [elementType]. If none are found, returns `null`.
  */
 public fun ASTNode.findChildByTypeRecursively(elementType: IElementType): ASTNode? =
-    recursiveChildren20.firstOrNull { it.elementType == elementType }
+    recursiveChildren.firstOrNull { it.elementType == elementType }
 
 /**
  * Returns the end offset of the text of this [ASTNode]
  */
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("endOffset20"),
-)
-public fun ASTNode.endOffset(): Int = endOffset20
-
-/**
- * Returns the end offset of the text of this [ASTNode]
- */
-public val ASTNode.endOffset20: Int // TODO: In Ktlint 2.0 replace with accessor without temporary suffix "20"
+public val ASTNode.endOffset: Int
     get(): Int = textRange.endOffset
 
 private val elementTypeCache = hashMapOf<IElementType, PsiElement>()
@@ -1070,27 +651,9 @@
  * Checks if the [AstNode] extends the [KtAnnotated] interface. Using this function to check the interface is more performant than checking
  * whether `psi is KtAnnotated` as the psi does not need to be derived from [ASTNode].
  */
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isKtAnnotated20"),
-)
-public fun ASTNode.isKtAnnotated(): Boolean = isKtAnnotated20
-
-/**
- * Checks if the [AstNode] extends the [KtAnnotated] interface. Using this function to check the interface is more performant than checking
- * whether `psi is KtAnnotated` as the psi does not need to be derived from [ASTNode].
- */
-public val ASTNode.isKtAnnotated20: Boolean
+public val ASTNode.isKtAnnotated: Boolean
     get(): Boolean = psiType { it is KtAnnotated }
 
-@Deprecated("Marked for removal in KtLint 2.0")
-public fun ASTNode.isKtExpression(): Boolean = psiType { it is KtExpression }
-
-@Deprecated("Marked for removal in KtLint 2.0")
-public fun ASTNode.isKtLoopExpression(): Boolean = psiType { it is KtLoopExpression }
-
 private inline fun ASTNode.psiType(predicate: (psiElement: PsiElement) -> Boolean): Boolean = predicate(dummyPsiElement())
 
 /**
@@ -1125,20 +688,9 @@
 private fun createDummyKtFile(): KtFile = KtlintKotlinCompiler.createPsiFileFromText("File.kt", "") as KtFile
 
 /**
- * Returns true if the receiver is not null, and it represents a declaration
- */
-@Deprecated(
-    "In Ktlint 2.0, it will be replaced with a property accessor. For easy migration replace current function call with " +
-        "the temporary property accessor. In 2.0 it can be replaced the final property accessor which will be the same as the " +
-        "current function name.",
-    replaceWith = ReplaceWith("isDeclaration20"),
-)
-public fun ASTNode?.isDeclaration(): Boolean = isDeclaration20
-
-/**
  * `true` if [ASTNode] is a declaration
  */
-public val ASTNode?.isDeclaration20: Boolean
+public val ASTNode?.isDeclaration: Boolean
     get(): Boolean = this != null && elementType in KtTokenSets.DECLARATION_TYPES
 
 /**
@@ -1151,12 +703,12 @@
 private fun ASTNode.isAnnotatedWithMaxLineLengthSuppression(): Boolean =
     (elementType == ANNOTATED_EXPRESSION && containsMaxLineLengthSuppression()) ||
         findChildByType(MODIFIER_LIST).containsMaxLineLengthSuppression() ||
-        (isRoot20 && findChildByType(FILE_ANNOTATION_LIST)?.containsMaxLineLengthSuppression() == true)
+        (isRoot && findChildByType(FILE_ANNOTATION_LIST)?.containsMaxLineLengthSuppression() == true)
 
 private fun ASTNode?.containsMaxLineLengthSuppression(): Boolean =
     this
         ?.findChildByType(ANNOTATION_ENTRY)
         ?.findChildByType(VALUE_ARGUMENT_LIST)
-        ?.children20
+        ?.children
         ?.any { it.elementType == VALUE_ARGUMENT && it.text == "\"ktlint:standard:max-line-length\"" }
         ?: false
diff --git a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/IndentConfig.kt b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/IndentConfig.kt
index 2d90adf..30e9b73 100644
--- a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/IndentConfig.kt
+++ b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/IndentConfig.kt
@@ -85,7 +85,7 @@
     /**
      * Get the indentation including the newline character for a node at the next indent level compared to the given node.
      */
-    public fun childIndentOf(node: ASTNode): String = node.indent20.plus(indent)
+    public fun childIndentOf(node: ASTNode): String = node.indent.plus(indent)
 
     /**
      * Get the indentation including the newline character for a node at the same indent level as the given node.
@@ -95,7 +95,7 @@
     /**
      * Get the indentation including the newline character for a node at the same indent level as the parent of the given node.
      */
-    public fun parentIndentOf(node: ASTNode): String = node.parent!!.indent20
+    public fun parentIndentOf(node: ASTNode): String = node.parent!!.indent
 
     /**
      * Converts [text] to a normalized indent. If [text] contains a new line, then only text after the last new line
diff --git a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/Rule.kt b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/Rule.kt
index a8a86e4..695e3e2 100644
--- a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/Rule.kt
+++ b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/Rule.kt
@@ -20,14 +20,6 @@
     public companion object {
         private const val DELIMITER = ":"
 
-        // TODO: Remove in 1.0 version when backward compatibility of rule id references can be dropped.
-        public fun prefixWithStandardRuleSetIdWhenMissing(id: String): String =
-            if (id.contains(DELIMITER)) {
-                id
-            } else {
-                "${RuleSetId.STANDARD.value}$DELIMITER$id"
-            }
-
         public fun isValid(value: String): Boolean = IdNamingPolicy.isValidRuleId(value)
     }
 }
@@ -232,7 +224,7 @@
 }
 
 @Deprecated(
-    message = "Only use for backward compatibility of custom ruleset JARs with Ktlint 2.x",
+    message = "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. Use RuleV2 when possible.",
     replaceWith = ReplaceWith("RuleV2"),
 )
 public open class Rule(
@@ -363,7 +355,7 @@
      */
     @Poko
     @Deprecated(
-        message = "Only use for backward compatibility of custom ruleset JARs with Ktlint 2.x",
+        message = "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. Use RuleV2.about when possible.",
         replaceWith = ReplaceWith("RuleV2.About"),
     )
     public class About(
@@ -383,8 +375,8 @@
 
     @Deprecated(
         message =
-            "Only used for backward compatibility of custom ruleset JARs with Ktlint 2.x. VisitorModifier is not used in Ktlint 2.x as " +
-                "due to the way that rules are executed, modifying the order in which rules are visited is not needed anymore.",
+            "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. VisitorModifiers are ignored by Ktlint 2.x " +
+                "as due to the way that rules are executed, modifying the order in which rules are visited is not needed anymore.",
     )
     public sealed class VisitorModifier {
         /**
@@ -394,8 +386,9 @@
         @Poko
         @Deprecated(
             message =
-                "Only used for backward compatibility of custom ruleset JARs with Ktlint 2.x. VisitorModifier is not used in Ktlint 2.x " +
-                    "as due to the way that rules are executed, modifying the order in which rules are visited is not needed anymore.",
+                "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. The RunAfterRule VisitorModifier is " +
+                    "ignored by Ktlint 2.x as due to the way that rules are executed, modifying the order in which rules are visited is " +
+                    "not needed anymore.",
         )
         public class RunAfterRule(
             /**
@@ -427,8 +420,9 @@
 
         @Deprecated(
             message =
-                "Only used for backward compatibility of custom ruleset JARs with Ktlint 2.x. VisitorModifier is not used in Ktlint 2.x " +
-                    "as due to the way that rules are executed, modifying the order in which rules are visited is not needed anymore.",
+                "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. The RunAsLateAsPossible VisitorModifier " +
+                    "is ignored by Ktlint 2.x as due to the way that rules are executed, modifying the order in which rules are visited " +
+                    "is not needed anymore.",
         )
         public object RunAsLateAsPossible : VisitorModifier()
     }
@@ -438,6 +432,9 @@
      * '.editorconfig' allows this rule specifically or all experimental rules. This interface is used by Ktlint internally but is also
      * explicitly meant to be used by custom rule providers.
      */
+    @Deprecated(
+        message = "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. Use RuleV2.Experimental when possible",
+    )
     public interface Experimental
 
     /**
@@ -445,6 +442,10 @@
      * '.editorconfig' contains property "code_style = ktlint_official" or when enabled explicitly. This interface is intended to be used
      * in Ktlint internally only. It may be subject to change at any time without providing any backward compatibility.
      */
+    @Deprecated(
+        message =
+            "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. Use RuleV2.OfficialCodeStyle when possible",
+    )
     public interface OfficialCodeStyle
 
     /**
@@ -452,5 +453,10 @@
      * deprecated, or when a rule is not applicable for general use.
      * This interface should not be used on a rule that is also marked with [Experimental], or [OfficialCodeStyle].
      */
+    @Deprecated(
+        message =
+            "Provides backwards compatibility of custom ruleset JARs created for Ktlint 1.x. Use RuleV2.OnlyWhenEnabledInEditorconfig " +
+                "when possible",
+    )
     public interface OnlyWhenEnabledInEditorconfig
 }
diff --git a/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt b/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt
index f52cb36..0d5de46 100644
--- a/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt
+++ b/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt
@@ -176,7 +176,7 @@
 
             val actual =
                 hasNewLineInClosedRange(
-                    enumClass.first { it.isWhiteSpaceWithNewline20 },
+                    enumClass.first { it.isWhiteSpaceWithNewline },
                     enumClass.last(),
                 )
 
@@ -212,7 +212,7 @@
             val actual =
                 hasNewLineInClosedRange(
                     enumBodyClass.first(),
-                    enumBodyClass.last { it.isWhiteSpaceWithNewline20 },
+                    enumBodyClass.last { it.isWhiteSpaceWithNewline },
                 )
 
             assertThat(actual).isTrue
@@ -456,7 +456,7 @@
                             ?.findChildByType(VALUE_PARAMETER)
                             ?.findChildByType(MODIFIER_LIST)
                             ?.findChildByType(ANNOTATION_ENTRY)
-                            ?.nextSibling20
+                            ?.nextSibling
                             ?.upsertWhitespaceBeforeMe(" ")
                     }.text
 
@@ -481,8 +481,8 @@
                             ?.upsertWhitespaceBeforeMe(" ")
                     }.findChildByType(CLASS)
                     ?.findChildByType(CLASS_BODY)
-                    ?.prevSibling20
-                    ?.let { it.isWhiteSpace20 && it.text == " " }
+                    ?.prevSibling
+                    ?.let { it.isWhiteSpace && it.text == " " }
                     ?: false
 
             assertThat(actual).isTrue()
@@ -653,8 +653,8 @@
                             ?.upsertWhitespaceAfterMe(" ")
                     }.findChildByType(FUN)
                     ?.findChildByType(VALUE_PARAMETER_LIST)
-                    ?.nextSibling20
-                    ?.let { it.isWhiteSpace20 && it.text == " " }
+                    ?.nextSibling
+                    ?.let { it.isWhiteSpace && it.text == " " }
                     ?: false
 
             assertThat(actual).isTrue()
@@ -676,11 +676,10 @@
 
         val actual =
             transformCodeToAST(code)
-                .firstChildLeafOrSelf20
+                .firstChildLeafOrSelf
                 .leaves()
                 .filter { it.elementType == IDENTIFIER }
-                .map { it.text to it.indent20 }
-                .toMap()
+                .associate { it.text to it.indent }
 
         assertThat(actual).contains(
             entry("Foo1", "\n"),
@@ -706,12 +705,12 @@
 
         val actual =
             transformCodeToAST(code)
-                .firstChildLeafOrSelf20
+                .firstChildLeafOrSelf
                 .leaves()
                 .filter { it.elementType == IDENTIFIER }
                 .map { identifier ->
                     identifier
-                        .leavesOnLine20
+                        .leavesOnLine
                         .joinToString(separator = "") { it.text }
                 }.toList()
 
@@ -741,10 +740,10 @@
 
             val actual =
                 transformCodeToAST(code)
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leaves()
                     .filter { it.elementType == IDENTIFIER }
-                    .map { identifier -> identifier.leavesOnLine20.lineLength }
+                    .map { identifier -> identifier.leavesOnLine.lineLength }
                     .toList()
 
             assertThat(actual).contains(
@@ -771,10 +770,10 @@
 
             val actual =
                 transformCodeToAST(code)
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leaves()
                     .filter { it.elementType == IDENTIFIER }
-                    .map { identifier -> identifier.leavesOnLine20.lineLength }
+                    .map { identifier -> identifier.leavesOnLine.lineLength }
                     .toList()
 
             assertThat(actual).contains(
@@ -801,12 +800,12 @@
 
             val actual =
                 transformCodeToAST(code)
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leaves()
                     .filter { it.elementType == IDENTIFIER }
                     .map { identifier ->
                         identifier
-                            .leavesOnLine20
+                            .leavesOnLine
                             .takeWhile { it.prevLeaf != identifier }
                             .lineLength
                     }.toList()
@@ -831,12 +830,12 @@
             assertThatNoException()
                 .isThrownBy {
                     transformCodeToAST(code)
-                        .firstChildLeafOrSelf20
+                        .firstChildLeafOrSelf
                         .leaves()
                         .filter { it.elementType == IDENTIFIER }
                         .map { identifier ->
                             identifier
-                                .leavesOnLine20
+                                .leavesOnLine
                                 .takeWhile { it.prevLeaf != identifier }
                                 .lineLength
                         }.toList()
@@ -861,10 +860,10 @@
 
             val actual =
                 transformCodeToAST(code)
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leaves()
                     .filter { it.elementType == IDENTIFIER }
-                    .map { identifier -> identifier.leavesOnLine20.lineLength }
+                    .map { identifier -> identifier.leavesOnLine.lineLength }
                     .toList()
 
             assertThat(actual).contains(
@@ -890,10 +889,10 @@
 
             val actual =
                 transformCodeToAST(code)
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leaves()
                     .filter { it.elementType == IDENTIFIER }
-                    .map { identifier -> identifier.leavesOnLine20.lineLength }
+                    .map { identifier -> identifier.leavesOnLine.lineLength }
                     .toList()
 
             assertThat(actual).contains(
@@ -919,10 +918,10 @@
 
             val actual =
                 transformCodeToAST(code)
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leaves()
                     .filter { it.elementType == IDENTIFIER }
-                    .map { identifier -> identifier.leavesOnLine20.dropTrailingEolComment().lineLength }
+                    .map { identifier -> identifier.leavesOnLine.dropTrailingEolComment().lineLength }
                     .toList()
 
             assertThat(actual).contains(
@@ -943,10 +942,10 @@
                 """.trimIndent()
             val actual =
                 transformCodeToAST(code)
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leavesForwardsIncludingSelf
                     .first { it.elementType == EOL_COMMENT }
-                    .leavesOnLine20
+                    .leavesOnLine
                     .dropTrailingEolComment()
                     .lineLength
 
@@ -1041,7 +1040,7 @@
 
         val actual =
             transformCodeToAST(code)
-                .lastChildLeafOrSelf20
+                .lastChildLeafOrSelf
                 .firstLeafOnLineOrSelf
                 .text
 
@@ -1107,7 +1106,7 @@
                 """.trimIndent()
             val result =
                 transformCodeToAST(code)
-                    .findChildByTypeRecursively(FUN, includeSelf = false)
+                    .findChildByTypeRecursively(FUN)
             assertThat(result).isNotNull()
         }
 
@@ -1121,7 +1120,7 @@
                 """.trimIndent()
             val result =
                 transformCodeToAST(code)
-                    .findChildByTypeRecursively(FUN, includeSelf = false)
+                    .findChildByTypeRecursively(FUN)
             assertThat(result).isNull()
         }
     }
@@ -1135,9 +1134,9 @@
 
         val actual = transformCodeToAST(code).findChildByType(CLASS)!!
 
-        assertThat(actual.isKtAnnotated20).isTrue()
-        assertThat(actual.findChildByType(CLASS_KEYWORD)!!.isKtAnnotated20).isFalse()
-        assertThat(actual.findChildByType(IDENTIFIER)!!.isKtAnnotated20).isFalse()
+        assertThat(actual.isKtAnnotated).isTrue()
+        assertThat(actual.findChildByType(CLASS_KEYWORD)!!.isKtAnnotated).isFalse()
+        assertThat(actual.findChildByType(IDENTIFIER)!!.isKtAnnotated).isFalse()
 
         assertThat(actual.isPsiType<KtAnnotated>()).isTrue()
         assertThat(actual.findChildByType(CLASS_KEYWORD)!!.isPsiType<KtAnnotated>()).isFalse()
@@ -1287,13 +1286,13 @@
         fileASTNode
             .findChildByType(CLASS)
             ?.findChildByType(CLASS_BODY)
-            ?.children20
+            ?.children
             .orEmpty()
 
     private fun toEnumClassSequence(fileASTNode: FileASTNode) =
         fileASTNode
             .findChildByType(CLASS)
-            ?.children20
+            ?.children
             .orEmpty()
 
     /**
diff --git a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintRuleEngine.kt b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintRuleEngine.kt
index 4c96a51..32fde86 100644
--- a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintRuleEngine.kt
+++ b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintRuleEngine.kt
@@ -11,7 +11,6 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CodeStyleValue
 import com.pinterest.ktlint.rule.engine.core.api.propertyTypes
 import com.pinterest.ktlint.rule.engine.core.util.safeAs
-import com.pinterest.ktlint.rule.engine.internal.AllAutocorrectHandler
 import com.pinterest.ktlint.rule.engine.internal.CodeFormatter
 import com.pinterest.ktlint.rule.engine.internal.EditorConfigFinder
 import com.pinterest.ktlint.rule.engine.internal.EditorConfigGenerator
@@ -96,25 +95,6 @@
     }
 
     /**
-     * Fix all style violations in [code] for lint errors when possible. If [code] is passed as file reference then the '.editorconfig'
-     * files on the path are taken into account. For each lint violation found, the [callback] is invoked.
-     *
-     * If [code] contains lint errors which have been autocorrected, then the resulting code is formatted again (up until
-     * [MAX_FORMAT_RUNS_PER_FILE] times) in order to fix lint errors that might result from the previous formatting run.
-     *
-     * [callback] is invoked once for each [LintError] found during any runs. As of that the [callback] might be invoked multiple times for
-     * the same [LintError].
-     *
-     * @throws KtLintParseException if text is not a valid Kotlin code
-     * @throws KtLintRuleException in case of internal failure caused by a bug in rule implementation
-     */
-    @Deprecated(message = "Marked for removal in Ktlint 2.0")
-    public fun format(
-        code: Code,
-        callback: (LintError, Boolean) -> Unit = { _, _ -> },
-    ): String = codeFormatter.format(code, AllAutocorrectHandler, callback, MAX_FORMAT_RUNS_PER_FILE)
-
-    /**
      * Formats style violations in [code]. Whenever a [LintError] is found the [callback] is invoked. If the [LintError] can be
      * autocorrected, the API Consumer determines whether that [LintError] is to autocorrected, or not.
      *
@@ -138,7 +118,7 @@
     ): String =
         codeFormatter.format(
             code = code,
-            autocorrectHandler = LintErrorAutocorrectHandler(defaultAutocorrect, callback),
+            autocorrectHandler = LintErrorAutocorrectHandler(callback),
             maxFormatRunsPerFile =
                 if (rerunAfterAutocorrect) {
                     MAX_FORMAT_RUNS_PER_FILE
diff --git a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtlintRuleEngineSuppression.kt b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtlintRuleEngineSuppression.kt
index ba8ce4b..e7a926b 100644
--- a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtlintRuleEngineSuppression.kt
+++ b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/api/KtlintRuleEngineSuppression.kt
@@ -1,7 +1,7 @@
 package com.pinterest.ktlint.rule.engine.api
 
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.internal.RuleExecutionContext
 import com.pinterest.ktlint.rule.engine.internal.insertKtlintRuleSuppression
@@ -43,7 +43,7 @@
         is KtlintSuppressionAtOffset -> {
             findLeafElementAt(suppression.offsetFromStartOf(text))
                 ?.let {
-                    if (it.isWhiteSpace20) {
+                    if (it.isWhiteSpace) {
                         // A suppression can not be added at a whitespace element. Insert it at the parent instead
                         it.parent
                     } else {
diff --git a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/AutocorrectHandler.kt b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/AutocorrectHandler.kt
index 3a14e16..b6e1cca 100644
--- a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/AutocorrectHandler.kt
+++ b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/AutocorrectHandler.kt
@@ -2,7 +2,6 @@
 
 import com.pinterest.ktlint.rule.engine.api.LintError
 import com.pinterest.ktlint.rule.engine.core.api.AutocorrectDecision
-import com.pinterest.ktlint.rule.engine.core.api.AutocorrectDecision.ALLOW_AUTOCORRECT
 import com.pinterest.ktlint.rule.engine.core.api.AutocorrectDecision.NO_AUTOCORRECT
 
 /**
@@ -19,16 +18,7 @@
     override fun autocorrectDecision(lintError: LintError) = NO_AUTOCORRECT
 }
 
-/**
- * Autocorrect all [LintError]s
- */
-internal data object AllAutocorrectHandler : AutocorrectHandler {
-    override fun autocorrectDecision(lintError: LintError) = ALLOW_AUTOCORRECT
-}
-
 internal class LintErrorAutocorrectHandler(
-    // TODO: remove unused variable autocorrectRuleWithoutAutocorrectApproveHandler
-    val autocorrectRuleWithoutAutocorrectApproveHandler: Boolean,
     private val callback: (LintError) -> AutocorrectDecision,
 ) : AutocorrectHandler {
     override fun autocorrectDecision(lintError: LintError) = callback(lintError)
diff --git a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/KtlintSuppression.kt b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/KtlintSuppression.kt
index 21a1378..9cba95d 100644
--- a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/KtlintSuppression.kt
+++ b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/KtlintSuppression.kt
@@ -26,13 +26,13 @@
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_PARAMETER_LIST
 import com.pinterest.ktlint.rule.engine.core.api.KtlintKotlinCompiler
 import com.pinterest.ktlint.rule.engine.core.api.findChildByTypeRecursively
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isRoot20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isRoot
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.replaceWith
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -159,8 +159,8 @@
                     // moved to the next list element. When no such element is found, it will be moved to the parent of the list type
                     targetPsiElement
                         .node
-                        .nextCodeSibling20
-                        ?.firstChildLeafOrSelf20
+                        .nextCodeSibling
+                        ?.firstChildLeafOrSelf
                         ?.psi
                 }
 
@@ -178,7 +178,7 @@
 private fun PsiElement.isIgnorableListElement() =
     node
         .takeIf { it.parent?.elementType in listTypeTokenSet }
-        ?.let { it.elementType == COMMA || it.isWhiteSpace20 || it.isPartOfComment20 }
+        ?.let { it.elementType == COMMA || it.isWhiteSpace || it.isPartOfComment }
         ?: false
 
 /**
@@ -220,7 +220,7 @@
         }
 
 private fun ASTNode.findSuppressionAnnotations(): Map<SuppressAnnotationType, ASTNode> =
-    if (isRoot20) {
+    if (isRoot) {
         findChildByType(FILE_ANNOTATION_LIST)
             ?.toMapOfSuppressionAnnotations()
             .orEmpty()
@@ -288,7 +288,7 @@
         }
 
         is KtClass, is KtFunction, is KtProperty, is KtPropertyAccessor -> {
-            this.addChild(PsiWhiteSpaceImpl(indent20), this.firstChildNode)
+            this.addChild(PsiWhiteSpaceImpl(indent), this.firstChildNode)
             val modifierListWithAnnotation = createModifierListWithAnnotationEntry(suppressType, suppressions)
             this.addChild(modifierListWithAnnotation, this.firstChildNode)
         }
@@ -303,7 +303,7 @@
             } else {
                 val modifierListWithAnnotation = createModifierListWithAnnotationEntry(suppressType, suppressions)
                 parent!!.addChild(modifierListWithAnnotation.findChildByType(ANNOTATION_ENTRY)!!, this)
-                parent!!.addChild(PsiWhiteSpaceImpl(indent20), this)
+                parent!!.addChild(PsiWhiteSpaceImpl(indent), this)
             }
         }
     }
@@ -326,7 +326,7 @@
         }
 
 private fun ASTNode.createFileAnnotationList(annotation: ASTNode) {
-    require(isRoot20) { "File annotation list can only be created for root node" }
+    require(isRoot) { "File annotation list can only be created for root node" }
     // Should always be inserted into the first (root) code child regardless in which root node the ktlint directive
     // was actually found
     findChildByType(PACKAGE_DIRECTIVE)
@@ -336,7 +336,7 @@
                 ?.addChild(annotation, packageDirective)
             packageDirective
                 .parent
-                ?.addChild(PsiWhiteSpaceImpl("\n" + indent20), packageDirective)
+                ?.addChild(PsiWhiteSpaceImpl("\n" + indent), packageDirective)
         }
 }
 
diff --git a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/RuleExecutionContext.kt b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/RuleExecutionContext.kt
index b1217cd..43f52cb 100644
--- a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/RuleExecutionContext.kt
+++ b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/RuleExecutionContext.kt
@@ -187,18 +187,6 @@
         }
     }
 
-    // Simplify the emitAndApprove to an emit only lambda which can be used in the legacy (deprecated) functions
-    @Deprecated(message = "Remove in Ktlint 2.0")
-    private fun ((offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision).onlyEmit() =
-        {
-            offset: Int,
-            errorMessage: String,
-            canBeAutoCorrected: Boolean,
-            ->
-            this(offset, errorMessage, canBeAutoCorrected)
-            Unit
-        }
-
     companion object {
         internal fun createRuleExecutionContext(
             ktLintRuleEngine: KtLintRuleEngine,
@@ -233,12 +221,6 @@
                 ktLintRuleEngine
                     .editorConfigLoader
                     .load(code.filePath)
-                    .also {
-                        // TODO: Remove warning below in KtLint 0.52 or later as some users skips multiple versions
-                        it.warnIfPropertyIsObsolete("disabled_rules", "0.49")
-                        // TODO: Remove warning below in KtLint 0.52 or later as some users skips multiple versions
-                        it.warnIfPropertyIsObsolete("ktlint_disabled_rules", "0.49")
-                    }
 
             val ruleProviders =
                 ktLintRuleEngine
@@ -277,18 +259,6 @@
     }
 }
 
-private fun EditorConfig.warnIfPropertyIsObsolete(
-    propertyName: String,
-    ktlintVersion: String,
-) {
-    if (this.contains(propertyName)) {
-        LOGGER.warn {
-            "Editorconfig property '$propertyName' is obsolete and is not used by KtLint starting from version $ktlintVersion. Remove " +
-                "the property from all '.editorconfig' files."
-        }
-    }
-}
-
 private class RuleExecutionException(
     val rule: RuleV2,
     val line: Int,
diff --git a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocator.kt b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocator.kt
index 58afde2..6fcc59f 100644
--- a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocator.kt
+++ b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocator.kt
@@ -10,10 +10,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleV2
 import com.pinterest.ktlint.rule.engine.core.api.TokenSets
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
-import com.pinterest.ktlint.rule.engine.core.api.isKtAnnotated20
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isKtAnnotated
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.recursiveChildren20
+import com.pinterest.ktlint.rule.engine.core.api.recursiveChildren
 import com.pinterest.ktlint.rule.engine.internal.SuppressionLocator.CommentSuppressionHint.Type.BLOCK_END
 import com.pinterest.ktlint.rule.engine.internal.SuppressionLocator.CommentSuppressionHint.Type.BLOCK_START
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -59,7 +59,7 @@
     private fun findSuppressionHints(rootNode: ASTNode): List<SuppressionHint> {
         val suppressionHints = ArrayList<SuppressionHint>()
         val commentSuppressionsHints = mutableListOf<CommentSuppressionHint>()
-        rootNode.recursiveChildren20.forEach { node ->
+        rootNode.recursiveChildren.forEach { node ->
             when (node.elementType) {
                 in TokenSets.COMMENTS -> {
                     node
@@ -142,7 +142,7 @@
                 if (rbraceOfContainingBlock == null) {
                     // Apply suppression on next sibling only, when the outer element does not end with a RBRACE
                     it.node
-                        .nextSibling20
+                        .nextSibling
                         .let { nextSibling ->
                             SuppressionHint(
                                 IntRange(
@@ -178,7 +178,7 @@
 
     private fun ASTNode.createSuppressionHintFromAnnotations(): SuppressionHint? {
         val suppressedRuleIds =
-            recursiveChildren20
+            recursiveChildren
                 .filter { it.elementType == VALUE_ARGUMENT }
                 .flatMapTo(mutableListOf()) {
                     it.text.removeSurrounding("\"").findRuleSuppressionIds()
@@ -186,7 +186,7 @@
 
         if (suppressedRuleIds.isEmpty()) return null
 
-        val owner = parent { it.isKtAnnotated20 } ?: return null
+        val owner = parent { it.isKtAnnotated } ?: return null
 
         val textRange = owner.textRange
 
@@ -211,8 +211,7 @@
                 // Disable specific rule. For backwards compatibility prefix rules without rule set id with the "standard" rule set
                 // id. Note that the KtlintSuppressionRule will emit a lint violation on the id. So this fix is only applicable for
                 // code bases in which the rule and suppression id's have not yet been fixed.
-                removePrefix("ktlint:")
-                    .let { listOf(RuleId.prefixWithStandardRuleSetIdWhenMissing(it)) }
+                listOf(removePrefix("ktlint:"))
             }
 
             else -> {
diff --git a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/rules/KtlintSuppressionRule.kt b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/rules/KtlintSuppressionRule.kt
index 62e115b..17ba917 100644
--- a/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/rules/KtlintSuppressionRule.kt
+++ b/ktlint-rule-engine/src/main/kotlin/com/pinterest/ktlint/rule/engine/internal/rules/KtlintSuppressionRule.kt
@@ -25,8 +25,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.findChildByTypeRecursively
 import com.pinterest.ktlint.rule.engine.core.api.findParentByType
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
@@ -130,7 +130,7 @@
 
     private fun ASTNode.removePrecedingWhitespace() {
         prevLeaf
-            .takeIf { it.isWhiteSpace20 }
+            .takeIf { it.isWhiteSpace }
             ?.remove()
     }
 
@@ -148,7 +148,7 @@
     ) {
         when (ktlintDirectiveType) {
             KTLINT_DISABLE -> {
-                if (node.elementType == EOL_COMMENT && node.prevLeaf.isWhiteSpaceWithNewline20) {
+                if (node.elementType == EOL_COMMENT && node.prevLeaf.isWhiteSpaceWithNewline) {
                     removeDanglingEolCommentWithKtlintDisableDirective(emit)
                 } else {
                     visitKtlintDisableDirective(emit)
@@ -208,7 +208,7 @@
             if (node.elementType == EOL_COMMENT) {
                 node.removePrecedingWhitespace()
             } else {
-                if (node.nextLeaf.isWhiteSpaceWithNewline20) {
+                if (node.nextLeaf.isWhiteSpaceWithNewline) {
                     node
                         .nextLeaf
                         ?.remove()
@@ -282,7 +282,7 @@
                     matchingKtlintEnabledDirective !=
                         node
                             .parent
-                            ?.nextSibling { !it.isWhiteSpace20 }
+                            ?.nextSibling { !it.isWhiteSpace }
                 }
                 ?: false
         }
diff --git a/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintTest.kt b/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintTest.kt
index 1b1b48d..e12dcb9 100644
--- a/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintTest.kt
+++ b/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/api/KtLintTest.kt
@@ -25,7 +25,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.END_OF_LINE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isRoot20
+import com.pinterest.ktlint.rule.engine.core.api.isRoot
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import org.assertj.core.api.Assertions.assertThat
 import org.ec4j.core.model.PropertyType
@@ -50,7 +50,7 @@
                         setOf(
                             RuleV2InstanceProvider {
                                 DummyRule { node ->
-                                    if (node.isRoot20) {
+                                    if (node.isRoot) {
                                         numberOfRootNodesVisited++
                                     }
                                 }
@@ -116,7 +116,7 @@
                         setOf(
                             RuleV2InstanceProvider {
                                 DummyRule { node ->
-                                    if (node.isRoot20) {
+                                    if (node.isRoot) {
                                         numberOfRootNodesVisited++
                                     }
                                 }
@@ -562,7 +562,7 @@
 
 private val ASTNode.visitNodeType: RuleExecutionCall.VisitNodeType
     get() =
-        if (isRoot20) {
+        if (isRoot) {
             ROOT
         } else {
             CHILD
diff --git a/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocatorTest.kt b/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocatorTest.kt
index dc4d1a2..7d0e747 100644
--- a/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocatorTest.kt
+++ b/ktlint-rule-engine/src/test/kotlin/com/pinterest/ktlint/rule/engine/internal/SuppressionLocatorTest.kt
@@ -70,7 +70,7 @@
     fun `Given that a NoFooIdentifierRule violation is suppressed with @Suppress at statement level for a specific rule then do not find a violation for that rule`() {
         val code =
             """
-            @Suppress("ktlint:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
+            @Suppress("ktlint:standard:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
             val fooNotReported = "foo"
 
             val fooReported = "foo"
@@ -85,7 +85,7 @@
     fun `Given that a NoFooIdentifierRule violation is suppressed with @Suppress at function level then do not find a violation for that rule in that function`() {
         val code =
             """
-            @Suppress("ktlint:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
+            @Suppress("ktlint:standard:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
             fun foo() {
                 val fooNotReported = "foo"
             }
@@ -119,7 +119,7 @@
     fun `Given that a NoFooIdentifierRule violation is suppressed with @Suppress at class level then do not find a violation for that rule in that class`() {
         val code =
             """
-            @Suppress("ktlint:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
+            @Suppress("ktlint:standard:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
             class Foo {
                 fun foo() {
                     val fooNotReported = "foo"
@@ -151,7 +151,7 @@
     fun `Given that the NoFooIdentifierRule is suppressed in the entire file with @file-colon-Suppress then do not find any NoFooIdentifierRule violation`() {
         val code =
             """
-            @file:Suppress("ktlint:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
+            @file:Suppress("ktlint:standard:no-foo-identifier-standard", "ktlint:$NON_STANDARD_RULE_SET_ID:no-foo-identifier")
 
             class Foo {
                 fun foo() {
@@ -341,7 +341,15 @@
             val actual = lint(code = code, ignoreKtlintSuppressionRule = false)
             @Suppress("ktlint:standard:max-line-length")
             assertThat(actual)
-                .containsExactly(LintError(1, 17, KTLINT_SUPPRESSION_RULE_ID, "Ktlint rule with id 'ktlint:internal:ktlint-suppression' is unknown or not loaded", false))
+                .containsExactly(
+                    LintError(
+                        1,
+                        17,
+                        KTLINT_SUPPRESSION_RULE_ID,
+                        "Ktlint rule with id 'ktlint:internal:ktlint-suppression' is unknown or not loaded",
+                        false,
+                    ),
+                )
         }
 
         @Test
@@ -353,8 +361,20 @@
             val actual = lint(code = code, ignoreKtlintSuppressionRule = false)
             @Suppress("ktlint:standard:max-line-length")
             assertThat(actual).containsExactly(
-                LintError(1, 4, KTLINT_SUPPRESSION_RULE_ID, "Directive 'ktlint-disable' is deprecated. Replace with @Suppress annotation", true),
-                LintError(1, 19, KTLINT_SUPPRESSION_RULE_ID, "Ktlint rule with id 'internal:ktlint-suppression' is unknown or not loaded", false),
+                LintError(
+                    1,
+                    4,
+                    KTLINT_SUPPRESSION_RULE_ID,
+                    "Directive 'ktlint-disable' is deprecated. Replace with @Suppress annotation",
+                    true,
+                ),
+                LintError(
+                    1,
+                    19,
+                    KTLINT_SUPPRESSION_RULE_ID,
+                    "Ktlint rule with id 'internal:ktlint-suppression' is unknown or not loaded",
+                    false,
+                ),
             )
         }
 
@@ -370,8 +390,20 @@
                 .containsExactly(
                     lintError(1, 5, "standard:no-foo-identifier-standard"),
                     lintError(1, 5, "$NON_STANDARD_RULE_SET_ID:no-foo-identifier"),
-                    LintError(1, 20, KTLINT_SUPPRESSION_RULE_ID, "Directive 'ktlint-disable' is deprecated. Replace with @Suppress annotation", true),
-                    LintError(1, 35, KTLINT_SUPPRESSION_RULE_ID, "Ktlint rule with id 'internal:ktlint-suppression' is unknown or not loaded", false),
+                    LintError(
+                        1,
+                        20,
+                        KTLINT_SUPPRESSION_RULE_ID,
+                        "Directive 'ktlint-disable' is deprecated. Replace with @Suppress annotation",
+                        true,
+                    ),
+                    LintError(
+                        1,
+                        35,
+                        KTLINT_SUPPRESSION_RULE_ID,
+                        "Ktlint rule with id 'internal:ktlint-suppression' is unknown or not loaded",
+                        false,
+                    ),
                 )
         }
     }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationRule.kt
index bc53894..40fa5e4 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationRule.kt
@@ -27,7 +27,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CodeStyleValue
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CommaSeparatedListValueParser
@@ -35,20 +35,20 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfigProperty
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -173,7 +173,7 @@
                 }
 
             node
-                .children20
+                .children
                 .filter { it.elementType == ANNOTATION_ENTRY }
                 .filter {
                     it.isAnnotationEntryWithValueArgumentListThatShouldBeWrapped() ||
@@ -190,7 +190,7 @@
                             index == 0 &&
                                 codeStyle == CodeStyleValue.ktlint_official &&
                                 it.annotationOnSameLineAsClosingParenthesisOfClassParameterList()
-                        }?.takeUnless { it.isWhiteSpaceWithNewline20 }
+                        }?.takeUnless { it.isWhiteSpaceWithNewline }
                         ?.let { prevLeaf ->
                             emit(prevLeaf.startOffset, "Expected newline before annotation", true)
                                 .ifAutocorrectAllowed {
@@ -207,12 +207,12 @@
                 }
 
             node
-                .children20
+                .children
                 .lastOrNull { it.elementType == ANNOTATION_ENTRY }
-                ?.lastChildLeafOrSelf20
+                ?.lastChildLeafOrSelf
                 ?.nextCodeLeaf
                 ?.prevLeaf
-                ?.takeUnless { it.isWhiteSpaceWithNewline20 }
+                ?.takeUnless { it.isWhiteSpaceWithNewline }
                 ?.let { prevLeaf ->
                     // Let the indentation rule determine the exact indentation and only report and fix when the line needs to be wrapped
                     emit(prevLeaf.startOffset, "Expected newline after last annotation", true)
@@ -223,16 +223,16 @@
 
             node
                 .takeIf { it.elementType == ANNOTATED_EXPRESSION }
-                ?.takeUnless { it.nextCodeSibling20?.elementType == OPERATION_REFERENCE }
-                ?.lastChildLeafOrSelf20
+                ?.takeUnless { it.nextCodeSibling?.elementType == OPERATION_REFERENCE }
+                ?.lastChildLeafOrSelf
                 ?.nextCodeLeaf
                 ?.prevLeaf
-                ?.takeUnless { it.isWhiteSpaceWithNewline20 }
+                ?.takeUnless { it.isWhiteSpaceWithNewline }
                 ?.let { leaf ->
                     // Let the indentation rule determine the exact indentation and only report and fix when the line needs to be wrapped
                     emit(leaf.startOffset, "Expected newline", true)
                         .ifAutocorrectAllowed {
-                            leaf.upsertWhitespaceBeforeMe(node.indent20)
+                            leaf.upsertWhitespaceBeforeMe(node.indent)
                         }
                 }
         }
@@ -245,7 +245,7 @@
 
     private fun ASTNode.hasAnnotationWithParameter(): Boolean {
         require(elementType in ANNOTATION_CONTAINER)
-        return children20
+        return children
             .any {
                 it.isAnnotationEntryWithValueArgumentListThatShouldBeWrapped() &&
                     it.parent?.parent?.elementType != VALUE_PARAMETER &&
@@ -256,7 +256,7 @@
 
     private fun ASTNode.hasMultipleAnnotationsOnSameLine(): Boolean {
         require(elementType in ANNOTATION_CONTAINER)
-        return children20
+        return children
             .any {
                 it.parent?.elementType != ANNOTATION &&
                     it.parent?.parent?.elementType != VALUE_PARAMETER &&
@@ -274,16 +274,16 @@
     private fun ASTNode.hasAnnotationBeforeConstructor() =
         codeStyle == CodeStyleValue.ktlint_official &&
             hasAnnotationEntry() &&
-            nextCodeSibling20?.elementType == CONSTRUCTOR_KEYWORD
+            nextCodeSibling?.elementType == CONSTRUCTOR_KEYWORD
 
-    private fun ASTNode.hasAnnotationEntry() = children20.any { it.elementType == ANNOTATION_ENTRY }
+    private fun ASTNode.hasAnnotationEntry() = children.any { it.elementType == ANNOTATION_ENTRY }
 
     private fun visitTypeArgumentList(
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .children20
+            .children
             .filter { it.elementType == TYPE_PROJECTION }
             .mapNotNull { it.findChildByType(TYPE_REFERENCE) }
             .filter { it.elementType == TYPE_REFERENCE }
@@ -298,11 +298,11 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .children20
+            .children
             .filter { it.elementType == TYPE_PROJECTION }
             .forEach { typeProjection ->
-                val prevLeaf = typeProjection.prevLeaf.takeIf { it.isWhiteSpace20 }
-                if (prevLeaf == null || prevLeaf.isWhiteSpaceWithoutNewline20) {
+                val prevLeaf = typeProjection.prevLeaf.takeIf { it.isWhiteSpace }
+                if (prevLeaf == null || prevLeaf.isWhiteSpaceWithoutNewline) {
                     emit(typeProjection.startOffset - 1, "Expected newline", true)
                         .ifAutocorrectAllowed {
                             typeProjection.upsertWhitespaceBeforeMe(indentConfig.childIndentOf(node))
@@ -313,8 +313,8 @@
         node
             .findChildByType(GT)
             ?.let { gt ->
-                val prevLeaf = gt.prevLeaf.takeIf { it.isWhiteSpace20 }
-                if (prevLeaf == null || prevLeaf.isWhiteSpaceWithoutNewline20) {
+                val prevLeaf = gt.prevLeaf.takeIf { it.isWhiteSpace }
+                if (prevLeaf == null || prevLeaf.isWhiteSpaceWithoutNewline) {
                     emit(gt.startOffset, "Expected newline", true)
                         .ifAutocorrectAllowed {
                             gt.upsertWhitespaceBeforeMe(indentConfig.childIndentOf(node))
@@ -339,7 +339,7 @@
                 true,
             ).ifAutocorrectAllowed {
                 node
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .upsertWhitespaceBeforeMe(getNewlineWithIndent(node.parent!!))
             }
         }
@@ -349,7 +349,7 @@
         val firstAnnotation = parent?.findChildByType(ANNOTATION_ENTRY)
         return siblings(forward = false)
             .takeWhile { it != firstAnnotation }
-            .any { it.isWhiteSpaceWithNewline20 }
+            .any { it.isWhiteSpaceWithNewline }
     }
 
     private fun ASTNode.isNotReceiverTargetAnnotation() = getAnnotationUseSiteTarget() != AnnotationUseSiteTarget.RECEIVER
@@ -393,17 +393,17 @@
     private fun ASTNode.isLastAnnotationEntry() =
         this ==
             parent
-                ?.children20
+                ?.children
                 ?.lastOrNull { it.elementType == ANNOTATION_ENTRY }
 
     private fun ASTNode.isPrecededByOtherAnnotationEntryWithoutParametersOnTheSameLine() =
         siblings(forward = false)
-            .takeWhile { !it.isWhiteSpaceWithNewline20 && !it.isAnnotationEntryWithValueArgumentListThatShouldBeWrapped() }
+            .takeWhile { !it.isWhiteSpaceWithNewline && !it.isAnnotationEntryWithValueArgumentListThatShouldBeWrapped() }
             .any { it.elementType == ANNOTATION_ENTRY && !it.isAnnotationEntryWithValueArgumentListThatShouldBeWrapped() }
 
     private fun ASTNode.isPrecededByOtherAnnotationEntryOnTheSameLine() =
         siblings(forward = false)
-            .takeWhile { !it.isWhiteSpaceWithNewline20 }
+            .takeWhile { !it.isWhiteSpaceWithNewline }
             .any { it.elementType == ANNOTATION_ENTRY }
 
     private fun ASTNode.isPrecededByOtherAnnotationEntry() =
@@ -413,7 +413,7 @@
     private fun ASTNode.isOnSameLineAsPreviousAnnotationEntry() =
         siblings(forward = false)
             .takeWhile { it.elementType != ANNOTATION_ENTRY }
-            .none { it.isWhiteSpaceWithNewline20 }
+            .none { it.isWhiteSpaceWithNewline }
 
     private fun ASTNode.isFollowedByOtherAnnotationEntry() = siblings(forward = true).any { it.elementType == ANNOTATION_ENTRY }
 
@@ -425,28 +425,28 @@
         //         FooBar()
         this
             ?.takeIf { it.parent?.elementType == CLASS }
-            ?.prevCodeSibling20
+            ?.prevCodeSibling
             ?.takeIf { it.elementType == COLON }
             ?.prevCodeLeaf
             ?.takeIf { it.elementType == RPAR }
             ?.prevLeaf
-            ?.isWhiteSpaceWithNewline20
+            ?.isWhiteSpaceWithNewline
             ?: false
 
     private fun ASTNode.isOnSameLineAsNextAnnotationEntry() =
         siblings(forward = true)
             .takeWhile { it.elementType != ANNOTATION_ENTRY }
-            .none { it.isWhiteSpaceWithNewline20 }
+            .none { it.isWhiteSpaceWithNewline }
 
     private fun visitFileAnnotationList(
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .lastChildLeafOrSelf20
+            .lastChildLeafOrSelf
             .nextCodeLeaf
             ?.let { codeLeaf ->
-                val whitespaceBefore = codeLeaf.prevLeaf { it.isWhiteSpace20 }
+                val whitespaceBefore = codeLeaf.prevLeaf { it.isWhiteSpace }
 
                 if (whitespaceBefore == null || whitespaceBefore.text != "\n\n") {
                     emit(
@@ -484,7 +484,7 @@
         val nodeBeforeAnnotations =
             modifierListRoot
                 .parent
-                ?.prevSibling20
+                ?.prevSibling
         // Make sure we only insert a single newline
         val indentWithoutNewline =
             nodeBeforeAnnotations
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationSpacingRule.kt
index ab57479..b7188d7 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/AnnotationSpacingRule.kt
@@ -8,16 +8,15 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.endOffset20
+import com.pinterest.ktlint.rule.engine.core.api.endOffset
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -67,50 +66,50 @@
         //      val s: Any
         //
         val whiteSpaces =
-            (annotations.asSequence().map { it.nextSibling20 } + node.nextSibling20)
+            (annotations.asSequence().map { it.nextSibling } + node.nextSibling)
                 .filterNotNull()
-                .filter { it.isWhiteSpace20 }
+                .filter { it.isWhiteSpace }
                 .take(annotations.size)
                 .toList()
 
         val next =
             node.nextSiblingWithAtLeastOneOf(
                 {
-                    !it.isWhiteSpace20 &&
+                    !it.isWhiteSpace &&
                         it.textLength > 0 &&
                         !it.isPartOf(FILE_ANNOTATION_LIST) &&
                         !it.isCommentOnSameLineAsPrevLeaf()
                 },
                 {
                     // Disallow multiple white spaces as well as comments
-                    if (it.isWhiteSpace20) {
+                    if (it.isWhiteSpace) {
                         val s = it.text
                         // Ensure at least one occurrence of two line breaks
                         s.indexOf("\n") != s.lastIndexOf("\n")
                     } else {
-                        it.isPartOfComment20 && !it.isCommentOnSameLineAsPrevLeaf()
+                        it.isPartOfComment && !it.isCommentOnSameLineAsPrevLeaf()
                     }
                 },
             )
         if (next != null) {
-            if (node.elementType != FILE_ANNOTATION_LIST && next.isPartOfComment20) {
-                emit(node.endOffset20, ERROR_MESSAGE, true)
+            if (node.elementType != FILE_ANNOTATION_LIST && next.isPartOfComment) {
+                emit(node.endOffset, ERROR_MESSAGE, true)
                     .ifAutocorrectAllowed {
                         // Special-case autocorrection when the annotation is separated from the annotated construct
                         // by a comment: we need to swap the order of the comment and the annotation
                         // Remove the annotation and the following whitespace
                         val eolComment = node.nextSibling { it.isCommentOnSameLineAsPrevLeaf() }
                         if (eolComment != null) {
-                            eolComment.prevSibling { it.isWhiteSpace20 }?.remove()
-                            eolComment.nextSibling { it.isWhiteSpace20 }?.remove()
+                            eolComment.prevSibling { it.isWhiteSpace }?.remove()
+                            eolComment.nextSibling { it.isWhiteSpace }?.remove()
                             eolComment.remove()
                         } else {
-                            node.nextSibling { it.isWhiteSpace20 }?.remove()
+                            node.nextSibling { it.isWhiteSpace }?.remove()
                         }
                         node.remove()
 
                         // Insert the annotation prior to the annotated construct
-                        val beforeAnchor = next.nextCodeSibling20
+                        val beforeAnchor = next.nextCodeSibling
                         next
                             .parent!!
                             .apply {
@@ -125,7 +124,7 @@
             }
         }
         if (node.elementType != FILE_ANNOTATION_LIST && whiteSpaces.any { it.containsMultipleNewlines() }) {
-            emit(node.endOffset20, ERROR_MESSAGE, true)
+            emit(node.endOffset, ERROR_MESSAGE, true)
                 .ifAutocorrectAllowed {
                     removeIntraLineBreaks(node, annotations.last())
                     removeExtraLineBreaks(node)
@@ -139,7 +138,7 @@
         p: (ASTNode) -> Boolean,
         needsToOccur: (ASTNode) -> Boolean,
     ): ASTNode? {
-        var node = this.nextSibling20
+        var node = this.nextSibling
         var occurrenceCount = 0
         while (node != null) {
             if (needsToOccur(node)) {
@@ -152,7 +151,7 @@
                     null
                 }
             }
-            node = node.nextSibling20
+            node = node.nextSibling
         }
         return null
     }
@@ -160,7 +159,7 @@
     private fun removeExtraLineBreaks(node: ASTNode) {
         val next =
             node.nextSibling {
-                it.isWhiteSpaceWithNewline20
+                it.isWhiteSpaceWithNewline
             } as? LeafPsiElement
         if (next != null) {
             rawReplaceExtraLineBreaks(next)
@@ -184,7 +183,7 @@
     ) {
         // Pull the next before raw replace, or it will blow up
         val nextLeaf = fromNode.nextLeaf
-        if (fromNode.isWhiteSpace20) {
+        if (fromNode.isWhiteSpace) {
             if (fromNode.text.toCharArray().count { it == '\n' } > 1) {
                 rawReplaceExtraLineBreaks(fromNode)
             }
@@ -196,7 +195,7 @@
     }
 
     private fun ASTNode.isCommentOnSameLineAsPrevLeaf() =
-        isPartOfComment20 && leaves(forward = false).takeWhile { it.isWhiteSpace20 }.none { "\n" in it.text }
+        isPartOfComment && leaves(forward = false).takeWhile { it.isWhiteSpace }.none { "\n" in it.text }
 }
 
 public val ANNOTATION_SPACING_RULE_ID: RuleId = AnnotationSpacingRule().ruleId
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ArgumentListWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ArgumentListWrappingRule.kt
index 78c7068..f16ae1a 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ArgumentListWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ArgumentListWrappingRule.kt
@@ -22,16 +22,16 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.lineLength
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
@@ -96,7 +96,7 @@
 
     private fun needToWrapArgumentList(node: ASTNode) =
         if ( // skip when there are no arguments
-            node.firstChildNode?.nextSibling20?.elementType != RPAR &&
+            node.firstChildNode?.nextSibling?.elementType != RPAR &&
             // skip lambda arguments
             node.parent?.elementType != FUNCTION_LITERAL &&
             // skip if number of arguments is big
@@ -114,9 +114,9 @@
     private fun ASTNode.exceedsMaxLineLength(): Boolean {
         if (textContains('\n')) return false
         require(this.elementType == VALUE_ARGUMENT_LIST)
-        val stopAtLeaf = findChildByType(RPAR)?.firstChildLeafOrSelf20
+        val stopAtLeaf = findChildByType(RPAR)?.firstChildLeafOrSelf
         return hasNoMaxLineLengthSuppression() &&
-            maxLineLength < leavesOnLine20.takeWhile { it.prevLeaf != stopAtLeaf }.lineLength
+            maxLineLength < leavesOnLine.takeWhile { it.prevLeaf != stopAtLeaf }.lineLength
     }
 
     private fun intendedIndent(child: ASTNode): String =
@@ -181,7 +181,7 @@
                 child
                     .prevLeaf
                     ?.let { prevLeaf ->
-                        if (prevLeaf.isWhiteSpaceWithNewline20) {
+                        if (prevLeaf.isWhiteSpaceWithNewline) {
                             emit(child.startOffset, errorMessage(child), true)
                                 .ifAutocorrectAllowed {
                                     prevLeaf.psi.delete()
@@ -200,13 +200,13 @@
                 val intendedIndent = intendedIndent(child)
                 val prevLeaf = child.prevWhiteSpaceWithNewLine() ?: child.prevLeaf
                 when {
-                    prevLeaf.isWhiteSpaceWithNewline20 -> {
+                    prevLeaf.isWhiteSpaceWithNewline -> {
                         // The current child is already wrapped to a new line. Checking and fixing the
                         // correct size of the indent is the responsibility of the IndentationRule.
                         return
                     }
 
-                    prevLeaf.isWhiteSpace20 -> {
+                    prevLeaf.isWhiteSpace -> {
                         // The current child needs to be wrapped to a newline.
                         emit(child.startOffset, errorMessage(child), true)
                             .ifAutocorrectAllowed {
@@ -246,7 +246,7 @@
                 child.isValueArgumentContaining(char)
         }
 
-    private fun ASTNode.isWhitespaceContaining(char: Char) = isWhiteSpace20 && textContains(char)
+    private fun ASTNode.isWhitespaceContaining(char: Char) = isWhiteSpace && textContains(char)
 
     private fun ASTNode.isCollectionLiteralContaining(char: Char) = elementType == COLLECTION_LITERAL_EXPRESSION && textContains(char)
 
@@ -257,7 +257,7 @@
         parent
             ?.findChildByType(TYPE_ARGUMENT_LIST)
             ?.children()
-            ?.any { it.isWhiteSpaceWithNewline20 } == true
+            ?.any { it.isWhiteSpaceWithNewline } == true
 
     private fun ASTNode.isPartOfDotQualifiedAssignmentExpression(): Boolean =
         parent
@@ -271,8 +271,8 @@
 
     private fun ASTNode.prevWhiteSpaceWithNewLine(): ASTNode? {
         var prev = prevLeaf
-        while (prev != null && (prev.isWhiteSpace20 || prev.isPartOfComment20)) {
-            if (prev.isWhiteSpaceWithNewline20) {
+        while (prev != null && (prev.isWhiteSpace || prev.isPartOfComment)) {
+            if (prev.isWhiteSpaceWithNewline) {
                 return prev
             }
             prev = prev.prevLeaf
@@ -283,7 +283,7 @@
     private fun ASTNode.isOnSameLineAsControlFlowKeyword(): Boolean {
         var prevLeaf = prevLeaf ?: return false
         while (prevLeaf.elementType !in TokenSets.CONTROL_FLOW_KEYWORDS) {
-            if (prevLeaf.isWhiteSpaceWithNewline20) return false
+            if (prevLeaf.isWhiteSpaceWithNewline) return false
             prevLeaf = prevLeaf.prevLeaf ?: return false
         }
         return true
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BackingPropertyNamingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BackingPropertyNamingRule.kt
index 43d9c50..17131f3 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BackingPropertyNamingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BackingPropertyNamingRule.kt
@@ -18,7 +18,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CodeStyleValue.android_studio
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
@@ -130,7 +130,7 @@
     }
 
     private fun ASTNode.findPropertyWithName(name: String) =
-        children20
+        children
             .filter { it.elementType == PROPERTY }
             .mapNotNull { it.findChildByType(IDENTIFIER) }
             .firstOrNull { it.text == name }
@@ -140,7 +140,7 @@
         parent
             ?.takeIf { it.elementType == OBJECT_DECLARATION }
             ?.findChildByType(MODIFIER_LIST)
-            ?.children20
+            ?.children
             ?.firstOrNull { it.elementType == COMPANION_KEYWORD }
 
     private fun ASTNode.findCorrelatedFunction(): ASTNode? {
@@ -158,7 +158,7 @@
     }
 
     private fun ASTNode.findFunctionWithName(name: String) =
-        children20
+        children
             .filter { it.elementType == FUN }
             .filter { it.hasNonEmptyParameterList() }
             .mapNotNull { it.findChildByType(IDENTIFIER) }
@@ -167,7 +167,7 @@
 
     private fun ASTNode.hasNonEmptyParameterList() =
         findChildByType(VALUE_PARAMETER_LIST)
-            ?.children20
+            ?.children
             ?.none { it.elementType == VALUE_PARAMETER }
             ?: false
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BinaryExpressionWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BinaryExpressionWrappingRule.kt
index 44cda4e..34351ce 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BinaryExpressionWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BinaryExpressionWrappingRule.kt
@@ -21,24 +21,24 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.dropTrailingEolComment
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isLeaf20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.isLeaf
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.lineLength
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.noNewLineInClosedRange
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -98,7 +98,7 @@
             ?.takeIf { binaryExpression ->
                 binaryExpression
                     .prevSibling { it.elementType == EQ }
-                    ?.let { noNewLineInClosedRange(it, binaryExpression.firstChildLeafOrSelf20) }
+                    ?.let { noNewLineInClosedRange(it, binaryExpression.firstChildLeafOrSelf) }
                     ?: false
             }?.takeIf { it.isOnLineExceedingMaxLineLength() }
             ?.let { expression ->
@@ -127,7 +127,7 @@
                 //         "tooLongToFitOnSingleLine" +
                 //             "bar",
                 //     )
-                node.prevLeaf.isWhiteSpaceWithNewline20
+                node.prevLeaf.isWhiteSpaceWithNewline
             }?.takeIf { it.causesMaxLineLengthToBeExceeded() }
             ?.let { expression ->
                 emit(
@@ -141,8 +141,8 @@
 
         // When left hand side is a call expression which causes the max line length to be exceeded then first wrap that expression
         node
-            .children20
-            .firstOrNull { !it.isLeaf20 || !it.isCode }
+            .children
+            .firstOrNull { !it.isLeaf || !it.isCode }
             ?.takeIf { it.elementType == CALL_EXPRESSION }
             ?.takeIf { it.causesMaxLineLengthToBeExceeded() }
             ?.let { callExpression -> visitCallExpression(callExpression, emit) }
@@ -161,8 +161,8 @@
         //   if (leftHandSideExpression && rightHandSideExpression) {
         parent
             ?.takeIf { it.elementType == CONDITION }
-            ?.lastChildLeafOrSelf20
-            ?.nextLeaf { it.isWhiteSpaceWithNewline20 }
+            ?.lastChildLeafOrSelf
+            ?.nextLeaf { it.isWhiteSpaceWithNewline }
             ?.prevLeaf
             ?.causesMaxLineLengthToBeExceeded()
             ?: false
@@ -211,7 +211,7 @@
                 // Allow:
                 //   val foo = "string too long to fit on the line" +
                 //       "more text"
-                it.nextSibling20.isWhiteSpaceWithNewline20
+                it.nextSibling.isWhiteSpaceWithNewline
             }?.takeIf { it.parent?.elementType == BINARY_EXPRESSION }
             ?.takeIf { binaryExpression ->
                 // Ignore binary expression inside raw string literals. Raw string literals are allowed to exceed max-line-length. Wrapping
@@ -220,8 +220,8 @@
             }?.let { operationReference ->
                 if (operationReference.firstChildNode.elementType == ELVIS) {
                     operationReference
-                        .prevLeaf { it.isWhiteSpace20 }
-                        .takeUnless { it.isWhiteSpaceWithNewline20 }
+                        .prevLeaf { it.isWhiteSpace }
+                        .takeUnless { it.isWhiteSpaceWithNewline }
                         ?.let {
                             // Wrapping after the elvis operator leads to violating the 'chain-wrapping' rule, so it must wrapped itself
                             emit(operationReference.startOffset, "Line is exceeding max line length. Break line before '?:'", true)
@@ -231,7 +231,7 @@
                         }
                 } else {
                     operationReference
-                        .nextSibling20
+                        .nextSibling
                         ?.let { nextSibling ->
                             emit(
                                 nextSibling.startOffset,
@@ -246,13 +246,13 @@
     }
 
     private fun ASTNode.isOnLineExceedingMaxLineLength() =
-        hasNoMaxLineLengthSuppression() && maxLineLength < leavesOnLine20.dropTrailingEolComment().lineLength
+        hasNoMaxLineLengthSuppression() && maxLineLength < leavesOnLine.dropTrailingEolComment().lineLength
 
     private fun ASTNode.causesMaxLineLengthToBeExceeded() =
         hasNoMaxLineLengthSuppression() &&
-            lastChildLeafOrSelf20
+            lastChildLeafOrSelf
                 .let { lastChildLeaf ->
-                    leavesOnLine20
+                    leavesOnLine
                         .dropTrailingEolComment()
                         .takeWhile { it.prevLeaf != lastChildLeaf }
                         .lineLength
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt
index b816ef0..5956d4d 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt
@@ -21,14 +21,14 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isDeclaration20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isDeclaration
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -122,7 +122,7 @@
         }
 
         if (node.elementType == FUN &&
-            (node.prevCodeSibling20?.elementType == EQ || node.prevCodeSibling20?.elementType == RETURN_KEYWORD)
+            (node.prevCodeSibling?.elementType == EQ || node.prevCodeSibling?.elementType == RETURN_KEYWORD)
         ) {
             // Allow:
             //   val foo =
@@ -148,12 +148,12 @@
         }
 
         node
-            .takeIf { it.isDeclaration20 }
+            .takeIf { it.isDeclaration }
             ?.takeUnless { it.prevLeaf.isBlankLine() }
             ?.let { insertBeforeNode ->
                 emit(insertBeforeNode.startOffset, "Expected a blank line for this declaration", true)
                     .ifAutocorrectAllowed {
-                        insertBeforeNode.upsertWhitespaceBeforeMe("\n".plus(node.indent20))
+                        insertBeforeNode.upsertWhitespaceBeforeMe("\n".plus(node.indent))
                     }
             }
     }
@@ -165,14 +165,14 @@
             parent
                 ?.takeIf { it.elementType == CLASS_BODY }
                 ?.findChildByType(LBRACE)
-                ?.nextCodeSibling20
+                ?.nextCodeSibling
 
     private fun ASTNode.isFirstCodeSiblingInBlock() =
         this ==
             parent
                 ?.takeIf { it.elementType == BLOCK }
                 ?.findChildByType(LBRACE)
-                ?.nextCodeSibling20
+                ?.nextCodeSibling
 
     private fun ASTNode.isFirstCodeSiblingInBodyOfFunctionLiteral() =
         this ==
@@ -181,12 +181,12 @@
                 ?.parent
                 ?.takeIf { it.elementType == FUNCTION_LITERAL }
                 ?.findChildByType(BLOCK)
-                ?.children20
+                ?.children
                 ?.firstOrNull { isCode }
 
     private fun ASTNode.isConsecutiveProperty() =
         takeIf { it.propertyRelated() }
-            ?.prevCodeSibling20
+            ?.prevCodeSibling
             ?.let { it.propertyRelated() || it.parent!!.propertyRelated() }
             ?: false
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBetweenWhenConditions.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBetweenWhenConditions.kt
index 979a0d7..7d4c4bf 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBetweenWhenConditions.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBetweenWhenConditions.kt
@@ -7,20 +7,20 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfigProperty
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesForwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -74,7 +74,7 @@
         emitAndApprove: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .children20
+            .children
             .filter { it.elementType == WHEN_ENTRY }
             // Blank lines should only be added *between* when-conditions, so first when-condition is to be skipped
             .drop(1)
@@ -82,7 +82,7 @@
                 whenEntry
                     .prevCodeLeaf
                     ?.leavesForwardsIncludingSelf
-                    ?.takeWhile { !it.isWhiteSpaceWithNewline20 }
+                    ?.takeWhile { !it.isWhiteSpaceWithNewline }
                     ?.last()
                     ?.nextLeaf
                     ?.takeUnless { it.containsBlankLine() }
@@ -92,39 +92,39 @@
                             "Add a blank line between all when-conditions in case at least one multiline when-condition is found in the statement",
                             true,
                         ).ifAutocorrectAllowed {
-                            whitespaceBeforeWhenEntry.upsertWhitespaceBeforeMe("\n${whenEntry.indent20}")
+                            whitespaceBeforeWhenEntry.upsertWhitespaceBeforeMe("\n${whenEntry.indent}")
                         }
                     }
             }
     }
 
-    private fun ASTNode.containsBlankLine(): Boolean = isWhiteSpace20 && text.count { it == '\n' } > 1
+    private fun ASTNode.containsBlankLine(): Boolean = isWhiteSpace && text.count { it == '\n' } > 1
 
     private fun ASTNode.hasAnyMultilineWhenCondition() =
-        children20
+        children
             .any { it.elementType == WHEN_ENTRY && (it.textContains('\n') || it.isPrecededByComment()) }
 
     private fun ASTNode.isPrecededByComment(): Boolean {
         // Check if this when-entry is preceded by a comment on its own line - not a trailing comment on the previous when-entry
-        val prevNonWhitespace = prevSibling { !it.isWhiteSpace20 }
-        if (prevNonWhitespace?.isPartOfComment20 != true) return false
+        val prevNonWhitespace = prevSibling { !it.isWhiteSpace }
+        if (prevNonWhitespace?.isPartOfComment != true) return false
 
         // Found a comment before this when-entry, so check whether it's on its own line
-        val whitespaceBeforeComment = prevNonWhitespace.prevSibling { it.isWhiteSpace20 }
+        val whitespaceBeforeComment = prevNonWhitespace.prevSibling { it.isWhiteSpace }
         return whitespaceBeforeComment?.text?.contains('\n') == true
     }
 
     private fun ASTNode.findWhitespaceAfterPreviousCodeSibling() =
-        prevCodeSibling20
-            ?.lastChildLeafOrSelf20
-            ?.nextLeaf { it.isWhiteSpace20 }
+        prevCodeSibling
+            ?.lastChildLeafOrSelf
+            ?.nextLeaf { it.isWhiteSpace }
 
     private fun removeBlankLinesBetweenWhenConditions(
         node: ASTNode,
         emitAndApprove: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .children20
+            .children
             .filter { it.elementType == WHEN_ENTRY }
             // Blank lines should only be removed *between* when-conditions, so first when-condition is to be skipped
             .drop(1)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CallExpressionWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CallExpressionWrappingRule.kt
index 89543a9..9c6097a 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CallExpressionWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CallExpressionWrappingRule.kt
@@ -1,7 +1,6 @@
 package com.pinterest.ktlint.ruleset.standard.rules
 
 import com.pinterest.ktlint.rule.engine.core.api.AutocorrectDecision
-import com.pinterest.ktlint.rule.engine.core.api.ElementType.ANNOTATION_ENTRY
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.ARROW
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.CALL_EXPRESSION
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.FUNCTION_LITERAL
@@ -9,18 +8,15 @@
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.LAMBDA_EXPRESSION
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.LBRACE
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.LPAR
-import com.pinterest.ktlint.rule.engine.core.api.ElementType.MODIFIER_LIST
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.RBRACE
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.REFERENCE_EXPRESSION
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.RPAR
-import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_ARGUMENT
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_ARGUMENT_LIST
 import com.pinterest.ktlint.rule.engine.core.api.IndentConfig
 import com.pinterest.ktlint.rule.engine.core.api.IndentConfig.Companion.DEFAULT_INDENT_CONFIG
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.RuleV2
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
-import com.pinterest.ktlint.rule.engine.core.api.children20
 import com.pinterest.ktlint.rule.engine.core.api.dropTrailingEolComment
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
@@ -28,20 +24,17 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.lineLength
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
-import org.jetbrains.kotlin.com.intellij.psi.PsiWhiteSpace
-import org.jetbrains.kotlin.psi.psiUtil.parents
 
 @SinceKtlint("2.0", SinceKtlint.Status.EXPERIMENTAL)
 public class CallExpressionWrappingRule :
@@ -94,17 +87,17 @@
         emit: (Int, String, Boolean) -> AutocorrectDecision,
     ) {
         require(node.elementType == VALUE_ARGUMENT_LIST)
-        if (node.textContains('\n') || node.exceedsMaxLineLength(node.lastChildLeafOrSelf20)) {
+        if (node.textContains('\n') || node.exceedsMaxLineLength(node.lastChildLeafOrSelf)) {
             node
                 .findChildByType(LPAR)
-                ?.takeUnless { it.nextSibling20.isWhiteSpaceWithNewline20 }
+                ?.takeUnless { it.nextSibling.isWhiteSpaceWithNewline }
                 ?.let { lpar ->
                     emit(lpar.startOffset, "Expected new line after '('", true)
                         .ifAutocorrectAllowed { lpar.upsertWhitespaceAfterMe(indentConfig.siblingIndentOf(lpar)) }
                 }
             node
                 .findChildByType(RPAR)
-                ?.takeUnless { it.prevSibling20.isWhiteSpaceWithNewline20 }
+                ?.takeUnless { it.prevSibling.isWhiteSpaceWithNewline }
                 ?.let { rbrace ->
                     emit(rbrace.startOffset, "Expected new line before ')'", true)
                         .ifAutocorrectAllowed {
@@ -119,24 +112,24 @@
         emit: (Int, String, Boolean) -> AutocorrectDecision,
     ) {
         require(node.elementType == LAMBDA_ARGUMENT)
-        if (node.textContains('\n') || node.exceedsMaxLineLength(node.lastChildLeafOrSelf20)) {
+        if (node.textContains('\n') || node.exceedsMaxLineLength(node.lastChildLeafOrSelf)) {
             val functionLiteral =
                 node
                     .findChildByType(LAMBDA_EXPRESSION)
                     ?.findChildByType(FUNCTION_LITERAL)
             val arrow = functionLiteral?.findChildByType(ARROW)
-            if (arrow == null || node.exceedsMaxLineLength(arrow.lastChildLeafOrSelf20)) {
+            if (arrow == null || node.exceedsMaxLineLength(arrow.lastChildLeafOrSelf)) {
                 // Arrow not found, or does not fit on the line. Wrap after brace
                 functionLiteral
                     ?.findChildByType(LBRACE)
-                    .takeUnless { it?.nextSibling20.isWhiteSpaceWithNewline20 }
+                    .takeUnless { it?.nextSibling.isWhiteSpaceWithNewline }
                     ?.let { lbrace ->
                         emit(lbrace.startOffset, "Expected new line after '{'", true)
                             .ifAutocorrectAllowed { lbrace.upsertWhitespaceAfterMe(indentConfig.siblingIndentOf(lbrace)) }
                     }
             } else {
                 arrow
-                    .takeUnless { it.nextSibling20.isWhiteSpaceWithNewline20 }
+                    .takeUnless { it.nextSibling.isWhiteSpaceWithNewline }
                     ?.let {
                         emit(arrow.startOffset + 1, "Expected new line after '->'", true)
                             .ifAutocorrectAllowed { arrow.upsertWhitespaceAfterMe(indentConfig.siblingIndentOf(arrow)) }
@@ -144,7 +137,7 @@
             }
             functionLiteral
                 ?.findChildByType(RBRACE)
-                ?.takeUnless { it.prevSibling20.isWhiteSpaceWithNewline20 }
+                ?.takeUnless { it.prevSibling.isWhiteSpaceWithNewline }
                 ?.let { rbrace ->
                     emit(rbrace.startOffset, "Expected new line before '}'", true)
                         .ifAutocorrectAllowed {
@@ -157,7 +150,7 @@
     private fun ASTNode.exceedsMaxLineLength(stopAtLeaf: ASTNode): Boolean =
         hasNoMaxLineLengthSuppression() &&
             maxLineLength <
-            leavesOnLine20
+            leavesOnLine
                 .dropTrailingEolComment()
                 .takeWhile { it.prevLeaf != stopAtLeaf }
                 .lineLength
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainMethodContinuationRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainMethodContinuationRule.kt
index 3d7e516..06b5fac 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainMethodContinuationRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainMethodContinuationRule.kt
@@ -30,7 +30,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.dropTrailingEolComment
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
@@ -38,22 +38,22 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.lineLength
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -160,18 +160,18 @@
 
     private fun ASTNode.isJavaClassReferenceExpression() =
         parent?.elementType == DOT_QUALIFIED_EXPRESSION &&
-            prevCodeSibling20?.elementType == CLASS_LITERAL_EXPRESSION &&
-            nextCodeSibling20?.elementType == REFERENCE_EXPRESSION &&
-            nextCodeSibling20?.firstChildLeafOrSelf20?.text == "java"
+            prevCodeSibling?.elementType == CLASS_LITERAL_EXPRESSION &&
+            nextCodeSibling?.elementType == REFERENCE_EXPRESSION &&
+            nextCodeSibling?.firstChildLeafOrSelf?.text == "java"
 
     private fun ASTNode.isReferenceExpression(): Boolean = parent?.isNestedReferenceExpression() ?: false
 
     private fun ASTNode.isNestedReferenceExpression(): Boolean =
         elementType == DOT_QUALIFIED_EXPRESSION &&
-            children20.first().let { it.elementType == REFERENCE_EXPRESSION || it.hasRightHandSideReferenceExpression() } &&
+            children.first().let { it.elementType == REFERENCE_EXPRESSION || it.hasRightHandSideReferenceExpression() } &&
             hasRightHandSideReferenceExpression()
 
-    private fun ASTNode.hasRightHandSideReferenceExpression() = children20.last().elementType == REFERENCE_EXPRESSION
+    private fun ASTNode.hasRightHandSideReferenceExpression() = children.last().elementType == REFERENCE_EXPRESSION
 
     private fun ChainedExpression.wrapBeforeChainOperator() =
         when {
@@ -219,7 +219,7 @@
         STRING_TEMPLATE ==
             chainOperators
                 .first()
-                .prevCodeSibling20
+                .prevCodeSibling
                 ?.elementType
 
     private fun ChainedExpression.exceedsMaxLineLength() =
@@ -245,9 +245,9 @@
                     chainOperators
                         .last()
                         .startOfLambdaArgumentInCallExpressionOrNull()
-                        ?: lastChildLeafOrSelf20.nextLeaf
+                        ?: lastChildLeafOrSelf.nextLeaf
                 hasNoMaxLineLengthSuppression() &&
-                    leavesOnLine20
+                    leavesOnLine
                         .dropTrailingEolComment()
                         .takeWhile { it.prevLeaf != stopAtLeaf }
                         .lineLength > maxLineLength
@@ -256,7 +256,7 @@
 
     private fun ASTNode.startOfLambdaArgumentInCallExpressionOrNull(): ASTNode? {
         require(elementType in chainOperatorTokenSet)
-        return nextCodeSibling20
+        return nextCodeSibling
             ?.takeIf { it.elementType == CALL_EXPRESSION }
             ?.findChildByType(LAMBDA_ARGUMENT)
             ?.findChildByType(LAMBDA_EXPRESSION)
@@ -264,7 +264,7 @@
             ?.findChildByType(LBRACE)
     }
 
-    private fun ASTNode.isPrecededByComment() = parent?.children20?.any { it.isPartOfComment20 } ?: false
+    private fun ASTNode.isPrecededByComment() = parent?.children?.any { it.isPartOfComment } ?: false
 
     private fun insertWhiteSpaceBeforeChainOperator(
         chainOperator: ASTNode,
@@ -275,7 +275,7 @@
             .takeUnless { it?.isCode == true }
             .let { whiteSpaceOrComment ->
                 when {
-                    whiteSpaceOrComment?.isPartOfComment20 == true -> {
+                    whiteSpaceOrComment?.isPartOfComment == true -> {
                         // In a chained method containing comments before each method in the chain starts on a newline
                         // Disallow:
                         //     fooBar
@@ -286,7 +286,7 @@
                             }
                     }
 
-                    whiteSpaceOrComment == null || whiteSpaceOrComment.isWhiteSpaceWithoutNewline20 -> {
+                    whiteSpaceOrComment == null || whiteSpaceOrComment.isWhiteSpaceWithoutNewline -> {
                         // In a multiline chained method each method in the chain starts on a newline
                         // Disallow:
                         //     fooBar
@@ -301,7 +301,7 @@
     }
 
     private fun ASTNode.shouldBeOnSameLineAsClosingElementOfPreviousExpressionInMethodChain() =
-        prevLeaf { !it.isWhiteSpace20 }
+        prevLeaf { !it.isWhiteSpace }
             ?.takeIf { it.elementType in groupClosingElementType }
             ?.let { closingElement ->
                 closingElement.isPrecededByNewline() ||
@@ -311,13 +311,13 @@
 
     private fun ASTNode.isPrecededByNewline() =
         prevLeaf
-            ?.isWhiteSpaceWithNewline20
+            ?.isWhiteSpaceWithNewline
             ?: false
 
     private fun ASTNode.isPartOfMultilineStringTemplate() =
         parent
             ?.takeIf { it.elementType == STRING_TEMPLATE }
-            ?.children20
+            ?.children
             ?.any { it.text == "\n" }
             ?: false
 
@@ -327,7 +327,7 @@
     ) {
         chainOperator
             .prevLeaf
-            .takeIf { it.isWhiteSpace20 }
+            .takeIf { it.isWhiteSpace }
             .let { whiteSpaceOrComment ->
                 // Disallow:
                 //     bar {
@@ -339,7 +339,7 @@
                 //     some text
                 //     """
                 //         .trimIndent()
-                if (whiteSpaceOrComment.isWhiteSpaceWithNewline20) {
+                if (whiteSpaceOrComment.isWhiteSpaceWithNewline) {
                     emit(chainOperator.startOffset, "Unexpected newline before '${chainOperator.text}'", true)
                         .ifAutocorrectAllowed { whiteSpaceOrComment?.remove() }
                 }
@@ -354,8 +354,8 @@
             .chainOperators
             .forEach { chainOperator ->
                 chainOperator
-                    .nextSibling { !it.isWhiteSpace20 }
-                    ?.takeIf { it.isPartOfComment20 }
+                    .nextSibling { !it.isWhiteSpace }
+                    ?.takeIf { it.isPartOfComment }
                     ?.let { emit(it.startOffset, "No comment expected at this location in method chain", false) }
             }
     }
@@ -369,7 +369,7 @@
             .forEach { chainOperator ->
                 chainOperator
                     .nextLeaf
-                    .takeIf { it.isWhiteSpaceWithNewline20 }
+                    .takeIf { it.isWhiteSpaceWithNewline }
                     ?.let { whiteSpace ->
                         emit(whiteSpace.startOffset - 1, "Unexpected newline after '${chainOperator.text}'", true)
                             .ifAutocorrectAllowed { whiteSpace.remove() }
@@ -409,7 +409,7 @@
             private fun ASTNode.toChainedExpression(): ChainedExpression? =
                 when (elementType) {
                     DOT_QUALIFIED_EXPRESSION, SAFE_ACCESS_EXPRESSION -> {
-                        children20
+                        children
                             .find { it.elementType in chainOperatorTokenSet }
                             ?.let { chainOperator ->
                                 createBaseChainedExpression(chainOperator).let { chainedExpression ->
@@ -423,7 +423,7 @@
                     }
 
                     CALL_EXPRESSION, ARRAY_ACCESS_EXPRESSION, PREFIX_EXPRESSION, POSTFIX_EXPRESSION -> {
-                        children20
+                        children
                             .mapNotNull { it.toChainedExpression() }
                             .singleOrNull()
                     }
@@ -434,12 +434,12 @@
                 }
 
             private fun ASTNode.createBaseChainedExpression(chainOperator: ASTNode): ChainedExpression {
-                val chainBefore = chainOperator.prevCodeSibling20?.toChainedExpression()
-                val chainAfter = chainOperator.nextCodeSibling20?.toChainedExpression()
+                val chainBefore = chainOperator.prevCodeSibling?.toChainedExpression()
+                val chainAfter = chainOperator.nextCodeSibling?.toChainedExpression()
                 val newlineAfter =
                     chainAfter.containsNewline() ||
-                        chainOperator.nextCodeSibling20!!.textContains('\n') ||
-                        chainOperator.nextSibling { it.isWhiteSpaceWithNewline20 } != null
+                        chainOperator.nextCodeSibling!!.textContains('\n') ||
+                        chainOperator.nextSibling { it.isWhiteSpaceWithNewline } != null
                 val chainOperators =
                     mutableListOf<ASTNode>()
                         .plus(chainBefore?.chainOperators.orEmpty())
@@ -461,7 +461,7 @@
             private fun ChainedExpression.modifyForFirstOperator(chainOperator: ASTNode): ChainedExpression =
                 copy(
                     hasNewlineBeforeFirstChainOperator =
-                        chainOperator.prevCodeSibling20!!.textContains('\n') || chainOperator.isPrecededByNewlineSibling(),
+                        chainOperator.prevCodeSibling!!.textContains('\n') || chainOperator.isPrecededByNewlineSibling(),
                     hasNewlineBetweenFirstAndLastChainOperator = false,
                 )
 
@@ -478,7 +478,7 @@
                     copy(hasNewlineBetweenFirstAndLastChainOperator = chainOperators.first().isPrecededByNewlineSibling())
                 }
 
-            private fun ASTNode.isPrecededByNewlineSibling() = prevSibling { it.isWhiteSpaceWithNewline20 } != null
+            private fun ASTNode.isPrecededByNewlineSibling() = prevSibling { it.isWhiteSpaceWithNewline } != null
 
             private fun ChainedExpression?.containsNewline() =
                 if (this == null) {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainWrappingRule.kt
index 9119a9c..952ba0e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ChainWrappingRule.kt
@@ -26,15 +26,15 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
@@ -76,11 +76,11 @@
     ) {
         val elementType = node.elementType
         if (nextLineTokens.contains(elementType)) {
-            if (node.isPartOfComment20) {
+            if (node.isPartOfComment) {
                 return
             }
             val nextLeaf = node.nextCodeLeaf?.prevLeaf
-            if (nextLeaf.isWhiteSpaceWithNewline20 && !node.isElvisOperatorAndComment()) {
+            if (nextLeaf.isWhiteSpaceWithNewline && !node.isElvisOperatorAndComment()) {
                 emit(node.startOffset, "Line must not end with \"${node.text}\"", true)
                     .ifAutocorrectAllowed {
                         // rewriting
@@ -99,7 +99,7 @@
                     }
             }
         } else if (sameLineTokens.contains(elementType) || prefixTokens.contains(elementType)) {
-            if (node.isPartOfComment20) {
+            if (node.isPartOfComment) {
                 return
             }
             val prevLeaf = node.prevLeaf
@@ -118,7 +118,7 @@
                 return
             }
 
-            if (prevLeaf != null && prevLeaf.isWhiteSpaceWithNewline20) {
+            if (prevLeaf != null && prevLeaf.isWhiteSpaceWithNewline) {
                 emit(node.startOffset, "Line must not begin with \"${node.text}\"", true)
                     .ifAutocorrectAllowed {
                         // rewriting
@@ -130,13 +130,13 @@
                         val nextLeaf = node.nextLeaf
                         val whiteSpaceToBeDeleted =
                             when {
-                                nextLeaf.isWhiteSpaceWithNewline20 -> {
+                                nextLeaf.isWhiteSpaceWithNewline -> {
                                     // Node is preceded and followed by whitespace. Prefer to remove the whitespace before the node as this will
                                     // change the indent of the next line
                                     prevLeaf
                                 }
 
-                                nextLeaf.isWhiteSpaceWithoutNewline20 -> {
+                                nextLeaf.isWhiteSpaceWithoutNewline -> {
                                     nextLeaf
                                 }
 
@@ -149,8 +149,8 @@
                         if (parent?.elementType == OPERATION_REFERENCE) {
                             val insertBeforeSibling =
                                 parent
-                                    .prevCodeSibling20
-                                    ?.nextSibling20
+                                    .prevCodeSibling
+                                    ?.nextSibling
                             parent.remove()
                             insertBeforeSibling?.parent?.addChild(parent, insertBeforeSibling)
                             parent.upsertWhitespaceBeforeMe(" ")
@@ -182,7 +182,7 @@
 
     private fun ASTNode.isElvisOperatorAndComment(): Boolean =
         elementType == ELVIS &&
-            leaves().takeWhile { it.isWhiteSpaceWithoutNewline20 || it.isPartOfComment20 }.any()
+            leaves().takeWhile { it.isWhiteSpaceWithoutNewline || it.isPartOfComment }.any()
 }
 
 public val CHAIN_WRAPPING_RULE_ID: RuleId = ChainWrappingRule().ruleId
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ClassSignatureRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ClassSignatureRule.kt
index a738e46..1624301 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ClassSignatureRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ClassSignatureRule.kt
@@ -27,7 +27,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CodeStyleValue.ktlint_official
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
@@ -39,21 +39,20 @@
 import com.pinterest.ktlint.rule.engine.core.api.hasModifier
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isLeaf20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isLeaf
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewlineOrNull
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevSibling
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
@@ -128,7 +127,7 @@
 
     private fun ASTNode.superTypes() =
         findChildByType(SUPER_TYPE_LIST)
-            ?.children20
+            ?.children
             ?.filter { it.isCode && it.elementType != COMMA }
 
     private fun ASTNode.hasMultilineSuperTypeList() = findChildByType(SUPER_TYPE_LIST)?.textContains('\n') == true
@@ -136,7 +135,7 @@
     private fun ASTNode.getFirstChildInSignature(): ASTNode? {
         findChildByType(MODIFIER_LIST)
             ?.let { modifierList ->
-                val iterator = modifierList.children20.iterator()
+                val iterator = modifierList.children.iterator()
                 var currentNode: ASTNode
                 while (iterator.hasNext()) {
                     currentNode = iterator.next()
@@ -148,7 +147,7 @@
                         return currentNode
                     }
                 }
-                return modifierList.nextCodeSibling20
+                return modifierList.nextCodeSibling
             }
         return nextCodeLeaf
     }
@@ -177,7 +176,7 @@
 
     private fun ASTNode.containsEolComment() =
         getPrimaryConstructorParameterListOrNull()
-            ?.children20
+            ?.children
             ?.any { it.elementType == EOL_COMMENT }
             ?: false
 
@@ -198,7 +197,7 @@
 
     private fun ASTNode.classSignatureExcludingSuperTypesIsMultiline() =
         classSignatureNodes(excludeSuperTypes = true)
-            .any { it.isWhiteSpaceWithNewline20 }
+            .any { it.isWhiteSpaceWithNewline }
 
     private fun ASTNode.getClassSignatureLength(excludeSuperTypes: Boolean) =
         indentWithoutNewlinePrefix.length + getClassSignatureNodesLength(excludeSuperTypes)
@@ -210,21 +209,21 @@
 
     private fun ASTNode.containsMultilineParameter(): Boolean =
         getPrimaryConstructorParameterListOrNull()
-            ?.children20
+            ?.children
             .orEmpty()
             .filter { it.elementType == VALUE_PARAMETER }
             .any { it.textContains('\n') }
 
     private fun ASTNode.containsAnnotatedParameter(): Boolean =
         getPrimaryConstructorParameterListOrNull()
-            ?.children20
+            ?.children
             .orEmpty()
             .filter { it.elementType == VALUE_PARAMETER }
             .any { it.isAnnotated() }
 
     private fun ASTNode.isAnnotated() =
         findChildByType(MODIFIER_LIST)
-            ?.children20
+            ?.children
             .orEmpty()
             .any { it.elementType == ANNOTATION_ENTRY }
 
@@ -239,7 +238,7 @@
         val primaryConstructorParameterList = node.getPrimaryConstructorParameterListOrNull()
         val hasNoValueParameters =
             primaryConstructorParameterList
-                ?.children20
+                ?.children
                 .orEmpty()
                 .none { it.elementType == VALUE_PARAMETER }
 
@@ -271,7 +270,7 @@
             ?.takeUnless {
                 // Allow:
                 //     class Foo constructor() { ... }
-                it.prevCodeSibling20?.elementType == CONSTRUCTOR_KEYWORD
+                it.prevCodeSibling?.elementType == CONSTRUCTOR_KEYWORD
             }?.takeUnless {
                 // Allow
                 //     class Foo() {
@@ -297,7 +296,7 @@
         return whiteSpaceCorrection
     }
 
-    private fun ASTNode.containsComment() = children20.any { it.isPartOfComment20 }
+    private fun ASTNode.containsComment() = children.any { it.isPartOfComment }
 
     private fun fixWhiteSpacesBeforeFirstParameterInValueParameterList(
         node: ASTNode,
@@ -310,14 +309,14 @@
         val valueParameterList = node.getPrimaryConstructorParameterListOrNull()
         val firstParameterInList =
             valueParameterList
-                ?.children20
+                ?.children
                 ?.first { it.elementType == VALUE_PARAMETER }
                 ?: return 0
 
         val firstParameter = firstParameterInList.firstChildNode
         firstParameter
             ?.prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             .let { whiteSpaceBeforeIdentifier ->
                 if (multiline) {
                     if (whiteSpaceBeforeIdentifier.isWhiteSpaceWithoutNewlineOrNull) {
@@ -361,19 +360,19 @@
         val valueParameterList = node.getPrimaryConstructorParameterListOrNull()
         val firstParameterInList =
             valueParameterList
-                ?.children20
+                ?.children
                 ?.first { it.elementType == VALUE_PARAMETER }
                 ?: return 0
 
         valueParameterList
-            .children20
+            .children
             .filter { it.elementType == VALUE_PARAMETER }
             .filter { it != firstParameterInList }
             .forEach { valueParameter ->
                 val firstChildNodeInValueParameter = valueParameter.firstChildNode
                 firstChildNodeInValueParameter
                     ?.prevLeaf
-                    ?.takeIf { it.isWhiteSpace20 }
+                    ?.takeIf { it.isWhiteSpace }
                     .let { whiteSpaceBeforeIdentifier ->
                         if (multiline) {
                             if (whiteSpaceBeforeIdentifier.isWhiteSpaceWithoutNewlineOrNull) {
@@ -419,13 +418,13 @@
                 .getPrimaryConstructorParameterListOrNull()
                 ?.findChildByType(RPAR)
         closingParenthesisPrimaryConstructor
-            ?.prevSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.prevSibling
+            ?.takeIf { it.isWhiteSpace }
             .let { whiteSpaceBeforeClosingParenthesis ->
                 if (multiline) {
                     if (whiteSpaceBeforeClosingParenthesis.isWhiteSpaceWithoutNewlineOrNull) {
                         // Let IndentationRule determine the exact indent
-                        val expectedParameterIndent = node.indent20
+                        val expectedParameterIndent = node.indent
                         if (!dryRun) {
                             emit(closingParenthesisPrimaryConstructor!!.startOffset, "Newline expected before closing parenthesis", true)
                                 .ifAutocorrectAllowed {
@@ -475,8 +474,8 @@
 
                             // Remove the whitespace before the super type call and do not insert a new whitespace as it will be fixed later
                             superTypeCallEntry
-                                .prevSibling20
-                                ?.takeIf { it.isWhiteSpace20 }
+                                .prevSibling
+                                ?.takeIf { it.isWhiteSpace }
                                 ?.remove()
 
                             superTypeList.addChild(superTypeCallEntry, superTypes.first())
@@ -499,8 +498,8 @@
                     .let { firstSuperType ->
                         firstSuperType
                             .prevLeaf
-                            .takeIf { it.isWhiteSpaceWithNewline20 }
-                            ?.takeUnless { it.prevSibling20?.elementType == EOL_COMMENT }
+                            .takeIf { it.isWhiteSpaceWithNewline }
+                            ?.takeUnless { it.prevSibling?.elementType == EOL_COMMENT }
                             ?.let { whiteSpaceBeforeSuperType ->
                                 val expectedWhitespace = " "
                                 if (whiteSpaceBeforeSuperType.text != expectedWhitespace) {
@@ -518,7 +517,7 @@
                     ?.let { superTypeFirstChildNode ->
                         superTypeFirstChildNode
                             .prevLeaf
-                            ?.takeIf { it.isWhiteSpace20 }
+                            ?.takeIf { it.isWhiteSpace }
                             .let { whiteSpaceBeforeIdentifier ->
                                 if (node.hasMultilineSuperTypeList() ||
                                     classSignaturesIncludingFirstSuperTypeExceedsMaxLineLength(node, emit)
@@ -550,7 +549,7 @@
                     val firstChildNodeInSuperType = superType.firstChildNode
                     firstChildNodeInSuperType
                         ?.prevLeaf
-                        ?.takeIf { it.isWhiteSpace20 }
+                        ?.takeIf { it.isWhiteSpace }
                         .let { whiteSpaceBeforeIdentifier ->
                             if (index == 0 && node.hasMultilinePrimaryConstructor()) {
                                 val expectedWhitespace = " "
@@ -610,8 +609,8 @@
         findChildByType(PRIMARY_CONSTRUCTOR)
             ?.findChildByType(VALUE_PARAMETER_LIST)
             ?.findChildByType(RPAR)
-            ?.prevLeaf { !it.isPartOfComment20 }
-            .isWhiteSpaceWithNewline20
+            ?.prevLeaf { !it.isPartOfComment }
+            .isWhiteSpaceWithNewline
 
     private fun fixClassBody(
         node: ASTNode,
@@ -636,10 +635,10 @@
     private fun List<ASTNode>.collectLeavesRecursively(): List<ASTNode> = flatMap { it.collectLeavesRecursively() }
 
     private fun ASTNode.collectLeavesRecursively(): List<ASTNode> =
-        if (isLeaf20) {
+        if (isLeaf) {
             listOf(this)
         } else {
-            children20
+            children
                 .flatMap { it.collectLeavesRecursively() }
                 .toList()
         }
@@ -677,7 +676,7 @@
 
     private fun ASTNode.countParameters() =
         getPrimaryConstructorParameterListOrNull()
-            ?.children20
+            ?.children
             .orEmpty()
             .count { it.elementType == VALUE_PARAMETER }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentSpacingRule.kt
index bc21db3..7a42872 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentSpacingRule.kt
@@ -5,7 +5,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
@@ -21,7 +21,7 @@
     ) {
         if (node.elementType == EOL_COMMENT) {
             val prevLeaf = node.prevLeaf
-            if (!prevLeaf.isWhiteSpace20 && prevLeaf is LeafPsiElement) {
+            if (!prevLeaf.isWhiteSpace && prevLeaf is LeafPsiElement) {
                 emit(node.startOffset, "Missing space before //", true)
                     .ifAutocorrectAllowed {
                         node.upsertWhitespaceBeforeMe(" ")
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentWrappingRule.kt
index 6227f8a..4253847 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/CommentWrappingRule.kt
@@ -10,13 +10,13 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNewLineInClosedRange
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
@@ -46,15 +46,15 @@
             val beforeBlockComment =
                 node
                     .leaves(false)
-                    .takeWhile { it.isWhiteSpaceWithoutNewline20 }
+                    .takeWhile { it.isWhiteSpaceWithoutNewline }
                     .firstOrNull()
-                    ?: node.firstChildLeafOrSelf20
+                    ?: node.firstChildLeafOrSelf
             val afterBlockComment =
                 node
                     .leaves()
-                    .takeWhile { it.isWhiteSpaceWithoutNewline20 }
+                    .takeWhile { it.isWhiteSpaceWithoutNewline }
                     .firstOrNull()
-                    ?: node.lastChildLeafOrSelf20
+                    ?: node.lastChildLeafOrSelf
 
             if (!beforeBlockComment.prevLeaf.isWhitespaceWithNewlineOrNull() &&
                 !afterBlockComment.nextLeaf.isWhitespaceWithNewlineOrNull()
@@ -107,13 +107,13 @@
                         "A block comment may not be followed by any other element on that same line",
                         true,
                     ).ifAutocorrectAllowed {
-                        nextLeaf.upsertWhitespaceBeforeMe(node.indent20)
+                        nextLeaf.upsertWhitespaceBeforeMe(node.indent)
                     }
                 }
         }
     }
 
-    private fun ASTNode?.isWhitespaceWithNewlineOrNull() = this == null || this.isWhiteSpaceWithNewline20
+    private fun ASTNode?.isWhitespaceWithNewlineOrNull() = this == null || this.isWhiteSpaceWithNewline
 }
 
 public val COMMENT_WRAPPING_RULE_ID: RuleId = CommentWrappingRule().ruleId
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverListWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverListWrappingRule.kt
index 5c2063b..f119ebf 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverListWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverListWrappingRule.kt
@@ -17,21 +17,21 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -93,14 +93,14 @@
         // Context receiver must be followed by new line or comment unless it is a type reference of a parameter
         node
             .takeUnless { it.isTypeReferenceParameterInFunction() }
-            ?.lastChildLeafOrSelf20
-            ?.nextLeaf { !it.isWhiteSpaceWithoutNewline20 && !it.isPartOfComment20 }
-            ?.takeIf { !it.isWhiteSpaceWithNewline20 }
+            ?.lastChildLeafOrSelf
+            ?.nextLeaf { !it.isWhiteSpaceWithoutNewline && !it.isPartOfComment }
+            ?.takeIf { !it.isWhiteSpaceWithNewline }
             ?.let { nodeAfterContextReceiver ->
                 emit(nodeAfterContextReceiver.startOffset, "Expected a newline after the context parameter", true)
                     .ifAutocorrectAllowed {
                         nodeAfterContextReceiver
-                            .firstChildLeafOrSelf20
+                            .firstChildLeafOrSelf
                             .upsertWhitespaceBeforeMe(indentConfig.parentIndentOf(node))
                     }
             }
@@ -111,7 +111,7 @@
             node.indentWithoutNewlinePrefix.length + node.textLength > maxLineLength
         ) {
             node
-                .children20
+                .children
                 .filter { it.elementType == VALUE_PARAMETER }
                 .forEach {
                     emit(
@@ -132,7 +132,7 @@
                         "Newline expected before closing parenthesis as max line length is violated",
                         true,
                     ).ifAutocorrectAllowed {
-                        rpar.upsertWhitespaceBeforeMe(node.indent20)
+                        rpar.upsertWhitespaceBeforeMe(node.indent)
                     }
                 }
         }
@@ -164,7 +164,7 @@
             node.indentWithoutNewlinePrefix.length + contextReceiverText.length > maxLineLength
         ) {
             node
-                .children20
+                .children
                 .filter { it.elementType == TYPE_PROJECTION }
                 .forEach {
                     emit(
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverWrappingRule.kt
index ffa39db..2721184 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ContextReceiverWrappingRule.kt
@@ -17,21 +17,21 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -94,14 +94,14 @@
         // Context receiver must be followed by new line or comment unless it is a type reference of a parameter
         node
             .takeUnless { it.isFunctionTypeReferenceInValueParameterList() }
-            ?.lastChildLeafOrSelf20
-            ?.nextLeaf { !it.isWhiteSpaceWithoutNewline20 && !it.isPartOfComment20 }
-            ?.takeIf { !it.isWhiteSpaceWithNewline20 }
+            ?.lastChildLeafOrSelf
+            ?.nextLeaf { !it.isWhiteSpaceWithoutNewline && !it.isPartOfComment }
+            ?.takeIf { !it.isWhiteSpaceWithNewline }
             ?.let { nodeAfterContextReceiver ->
                 emit(nodeAfterContextReceiver.startOffset, "Expected a newline after the context receiver", true)
                     .ifAutocorrectAllowed {
                         nodeAfterContextReceiver
-                            .firstChildLeafOrSelf20
+                            .firstChildLeafOrSelf
                             .upsertWhitespaceBeforeMe(indentConfig.parentIndentOf(node))
                     }
             }
@@ -112,7 +112,7 @@
             node.indentWithoutNewlinePrefix.length + node.textLength > maxLineLength
         ) {
             node
-                .children20
+                .children
                 .filter { it.elementType == CONTEXT_RECEIVER }
                 .forEach {
                     emit(
@@ -133,7 +133,7 @@
                         "Newline expected before closing parenthesis as max line length is violated",
                         true,
                     ).ifAutocorrectAllowed {
-                        rpar.upsertWhitespaceBeforeMe(node.indent20)
+                        rpar.upsertWhitespaceBeforeMe(node.indent)
                     }
                 }
         }
@@ -163,7 +163,7 @@
             node.indentWithoutNewlinePrefix.length + contextReceiverText.length > maxLineLength
         ) {
             node
-                .children20
+                .children
                 .filter { it.elementType == TYPE_PROJECTION }
                 .forEach {
                     emit(
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/EnumWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/EnumWrappingRule.kt
index d1d8cc3..c7ef248 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/EnumWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/EnumWrappingRule.kt
@@ -13,18 +13,18 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasModifier
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.leavesForwardsIncludingSelf
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
@@ -87,13 +87,13 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ): Boolean {
-        val firstEnumEntry = node.findChildByType(ENUM_ENTRY)?.firstChildLeafOrSelf20
+        val firstEnumEntry = node.findChildByType(ENUM_ENTRY)?.firstChildLeafOrSelf
         if (firstEnumEntry != null) {
             node
-                .firstChildLeafOrSelf20
+                .firstChildLeafOrSelf
                 .leavesForwardsIncludingSelf
                 .takeWhile { it != firstEnumEntry }
-                .firstOrNull { it.isPartOfComment20 }
+                .firstOrNull { it.isPartOfComment }
                 ?.let { commentBeforeFirstEnumEntry ->
                     val expectedIndent = indentConfig.childIndentOf(node)
                     if (commentBeforeFirstEnumEntry.prevLeaf?.text != expectedIndent) {
@@ -111,26 +111,26 @@
     private fun ASTNode.isMultiline() = text.contains('\n')
 
     private fun ASTNode.hasAnnotatedEnumEntry() =
-        children20
+        children
             .filter { it.elementType == ENUM_ENTRY }
             .any { it.isAnnotated() }
 
     private fun ASTNode.isAnnotated(): Boolean =
         findChildByType(MODIFIER_LIST)
-            ?.children20
+            ?.children
             .orEmpty()
             .any { it.elementType == ANNOTATION_ENTRY }
 
-    private fun ASTNode.hasCommentedEnumEntry() = children20.any { it.containsCommentInEnumEntry() }
+    private fun ASTNode.hasCommentedEnumEntry() = children.any { it.containsCommentInEnumEntry() }
 
-    private fun ASTNode.containsCommentInEnumEntry() = children20.any { it.isPartOfComment20 }
+    private fun ASTNode.containsCommentInEnumEntry() = children.any { it.isPartOfComment }
 
     private fun wrapEnumEntries(
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .children20
+            .children
             .filter { it.elementType == ENUM_ENTRY }
             .forEach { enumEntry ->
                 wrapEnumEntry(enumEntry, emit)
@@ -142,8 +142,8 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .prevLeaf { !it.isPartOfComment20 && !it.isWhiteSpaceWithoutNewline20 }
-            ?.takeUnless { it.isWhiteSpaceWithNewline20 }
+            .prevLeaf { !it.isPartOfComment && !it.isWhiteSpaceWithoutNewline }
+            ?.takeUnless { it.isWhiteSpaceWithNewline }
             ?.let { prevLeaf ->
                 emit(node.startOffset, "Enum entry should start on a separate line", true)
                     .ifAutocorrectAllowed {
@@ -175,10 +175,10 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .children20
+            .children
             .lastOrNull { it.elementType == ENUM_ENTRY }
-            ?.nextSibling { !it.isPartOfComment20 }
-            ?.takeUnless { it.nextCodeSibling20?.elementType == RBRACE }
+            ?.nextSibling { !it.isPartOfComment }
+            ?.takeUnless { it.nextCodeSibling?.elementType == RBRACE }
             ?.let { nextSibling ->
                 val expectedIndent = "\n".plus(indentConfig.siblingIndentOf(node))
                 if (nextSibling.text != expectedIndent) {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ExpressionOperandWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ExpressionOperandWrappingRule.kt
index 8f6a1e3..678e77a 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ExpressionOperandWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ExpressionOperandWrappingRule.kt
@@ -10,19 +10,19 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleV2
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesInClosedRange
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -91,17 +91,17 @@
     ) {
         node
             .findChildByType(OPERATION_REFERENCE)
-            ?.takeUnless { it.nextSibling20.isWhiteSpaceWithNewline20 }
+            ?.takeUnless { it.nextSibling.isWhiteSpaceWithNewline }
             ?.takeUnless {
-                it.nextSibling20.isWhiteSpaceWithoutNewline20 &&
-                    it.nextSibling20?.nextSibling20?.elementType == EOL_COMMENT
+                it.nextSibling.isWhiteSpaceWithoutNewline &&
+                    it.nextSibling?.nextSibling?.elementType == EOL_COMMENT
             }?.let { operationReference ->
                 val startOffset =
                     with(operationReference) { startOffset + textLength }
                         .plus(
                             operationReference
-                                .nextSibling20
-                                ?.takeIf { it.isWhiteSpace20 }
+                                .nextSibling
+                                ?.takeIf { it.isWhiteSpace }
                                 ?.textLength
                                 ?: 0,
                         )
@@ -120,13 +120,13 @@
         }
 
         return anyParentBinaryExpression { parent ->
-            parent.children20.any { it.isWhiteSpaceWithNewline20 }
+            parent.children.any { it.isWhiteSpaceWithNewline }
         }
     }
 
-    private fun ASTNode.leftHandSide() = children20.firstOrNull { it.isCode }
+    private fun ASTNode.leftHandSide() = children.firstOrNull { it.isCode }
 
-    private fun ASTNode.rightHandSide() = children20.lastOrNull { it.isCode }
+    private fun ASTNode.rightHandSide() = children.lastOrNull { it.isCode }
 
     private fun ASTNode?.isMultilineOperand() =
         when {
@@ -135,8 +135,8 @@
             }
 
             else -> {
-                leavesInClosedRange(this.firstChildLeafOrSelf20, this.lastChildLeafOrSelf20)
-                    .any { it.isWhiteSpaceWithNewline20 }
+                leavesInClosedRange(this.firstChildLeafOrSelf, this.lastChildLeafOrSelf)
+                    .any { it.isWhiteSpaceWithNewline }
             }
         }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FilenameRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FilenameRule.kt
index 0434a9a..4063433 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FilenameRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FilenameRule.kt
@@ -11,8 +11,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.TYPE_REFERENCE
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
-import com.pinterest.ktlint.rule.engine.core.api.children20
-import com.pinterest.ktlint.rule.engine.core.api.isRoot20
+import com.pinterest.ktlint.rule.engine.core.api.children
+import com.pinterest.ktlint.rule.engine.core.api.isRoot
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import com.pinterest.ktlint.ruleset.standard.rules.internal.regExIgnoringDiacriticsAndStrokesOnLetters
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -49,7 +49,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isRoot20) {
+        if (node.isRoot) {
             node as FileASTNode? ?: error("node is not ${FileASTNode::class} but ${node::class}")
 
             val filePath = (node.psi as? KtFile)?.virtualFilePath
@@ -99,7 +99,7 @@
     }
 
     private fun ASTNode.topLevelDeclarations(elementType: IElementType? = null): List<TopLevelDeclaration> =
-        children20
+        children
             .filter { elementType == null || it.elementType == elementType }
             .filter { it.doesNotHavePrivateModifier() }
             .mapNotNull { it.toTopLevelDeclaration() }
@@ -108,12 +108,12 @@
 
     private fun ASTNode.doesNotHavePrivateModifier(): Boolean =
         findChildByType(MODIFIER_LIST)
-            ?.children20
+            ?.children
             ?.none { it.text == "private" }
             ?: true
 
     private fun ASTNode.hasTopLevelDeclarationNotExtending(className: String) =
-        children20
+        children
             .filter { it.doesNotHavePrivateModifier() }
             .any { it.isNotClassRelatedTopLevelDeclaration() || it.isFunctionNotExtending(className) }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FinalNewlineRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FinalNewlineRule.kt
index 2d2991f..9327c59 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FinalNewlineRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FinalNewlineRule.kt
@@ -7,10 +7,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INSERT_FINAL_NEWLINE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isRoot20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isRoot
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -32,21 +32,21 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isRoot20) {
+        if (node.isRoot) {
             if (node.textLength == 0) {
                 stopTraversalOfAST()
                 return
             }
             val lastNode = lastChildNodeOf(node)
             when {
-                insertFinalNewline && (!lastNode.isWhiteSpace20 || lastNode.isWhiteSpaceWithoutNewline20) -> {
+                insertFinalNewline && (!lastNode.isWhiteSpace || lastNode.isWhiteSpaceWithoutNewline) -> {
                     emit(node.textLength - 1, "File must end with a newline (\\n)", true)
                         .ifAutocorrectAllowed {
                             node.addChild(PsiWhiteSpaceImpl("\n"), null)
                         }
                 }
 
-                !insertFinalNewline && lastNode != null && lastNode.isWhiteSpaceWithNewline20 -> {
+                !insertFinalNewline && lastNode != null && lastNode.isWhiteSpaceWithNewline -> {
                     emit(lastNode.startOffset, "Redundant newline (\\n) at the end of file", true)
                         .ifAutocorrectAllowed { lastNode.remove() }
                 }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionExpressionBodyRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionExpressionBodyRule.kt
index e4ab229..41a9db0 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionExpressionBodyRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionExpressionBodyRule.kt
@@ -17,19 +17,19 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesInClosedRange
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -107,7 +107,7 @@
             ?.takeUnless { it.countReturnKeywords() > 1 }
             ?.findChildByType(RETURN)
             ?.findChildByType(RETURN_KEYWORD)
-            ?.nextSibling { !it.isWhiteSpace20 }
+            ?.nextSibling { !it.isWhiteSpace }
             ?.let { codeSibling ->
                 emit(block.startOffset, "Function body should be replaced with body expression", true)
                     .ifAutocorrectAllowed {
@@ -129,8 +129,8 @@
                         with(block.parent!!) {
                             // Remove whitespace before block
                             block
-                                .prevSibling20
-                                .takeIf { it.isWhiteSpace20 }
+                                .prevSibling
+                                .takeIf { it.isWhiteSpace }
                                 ?.remove()
                             if (findChildByType(TYPE_REFERENCE) == null) {
                                 // Insert Unit as return type as otherwise a compilation error results
@@ -150,13 +150,13 @@
 
     private fun ASTNode.containingOnly(iElementType: IElementType) =
         iElementType ==
-            children20
-                .filterNot { it.elementType == LBRACE || it.elementType == RBRACE || it.isWhiteSpace20 }
+            children
+                .filterNot { it.elementType == LBRACE || it.elementType == RBRACE || it.isWhiteSpace }
                 .singleOrNull()
                 ?.elementType
 
     private fun ASTNode.countReturnKeywords() =
-        leavesInClosedRange(firstChildLeafOrSelf20, lastChildLeafOrSelf20)
+        leavesInClosedRange(firstChildLeafOrSelf, lastChildLeafOrSelf)
             .count { it.elementType == RETURN_KEYWORD }
 
     private fun createUnitTypeReference() =
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionLiteralRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionLiteralRule.kt
index 24c7c20..8074325 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionLiteralRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionLiteralRule.kt
@@ -19,7 +19,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.dropTrailingEolComment
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
@@ -27,24 +27,23 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.findParentByType
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewlineOrNull
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesForwardsIncludingSelf
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.lineLength
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -132,7 +131,7 @@
     ) {
         val valueParameters =
             parameterList
-                .children20
+                .children
                 .filter { it.elementType == VALUE_PARAMETER }
         if (valueParameters.count() > 1 || parameterList.wrapFirstParameterToNewline()) {
             if (parameterList.textContains('\n') || parameterList.doesNotFitOnSameLineAsStartOfFunctionLiteral()) {
@@ -179,7 +178,7 @@
         require(elementType == VALUE_PARAMETER_LIST && parent?.elementType == FUNCTION_LITERAL)
         val lbrace = parent?.findChildByType(LBRACE)!!
         return lbrace
-            .leavesOnLine20
+            .leavesOnLine
             .dropTrailingEolComment()
             .takeWhile { it.prevLeaf != lbrace }
             .lineLength
@@ -187,12 +186,12 @@
 
     private fun ASTNode.lengthOfParameterListWhenOnSingleLine(): Int {
         require(elementType == VALUE_PARAMETER_LIST)
-        val stopAtLeaf = lastChildLeafOrSelf20.nextLeaf
-        return firstChildLeafOrSelf20
+        val stopAtLeaf = lastChildLeafOrSelf.nextLeaf
+        return firstChildLeafOrSelf
             .leavesForwardsIncludingSelf
             .takeWhile { it != stopAtLeaf }
             .joinToString(separator = "") {
-                if (it.isWhiteSpace20) {
+                if (it.isWhiteSpace) {
                     // Eliminate newlines and redundant spaces
                     " "
                 } else {
@@ -206,7 +205,7 @@
         val stopAtLeaf = nextSibling { it.elementType == RBRACE }
         return hasNoMaxLineLengthSuppression() &&
             maxLineLength <
-            leavesOnLine20
+            leavesOnLine
                 .dropTrailingEolComment()
                 .takeWhile { it.prevLeaf != stopAtLeaf }
                 .lineLength
@@ -219,11 +218,11 @@
             //        bar()
             //    }
             val stopAtLeaf =
-                children20
+                children
                     .first { it.elementType == VALUE_PARAMETER }
-                    .lastChildLeafOrSelf20
-                    .nextLeaf { !it.isWhiteSpaceWithoutNewline20 && !it.isPartOfComment20 }
-            leavesOnLine20
+                    .lastChildLeafOrSelf
+                    .nextLeaf { !it.isWhiteSpaceWithoutNewline && !it.isPartOfComment }
+            leavesOnLine
                 .dropTrailingEolComment()
                 .takeWhile { it.prevLeaf != stopAtLeaf }
                 .lineLength
@@ -248,7 +247,7 @@
     ) {
         require(parameterList.elementType == VALUE_PARAMETER_LIST)
         parameterList
-            .children20
+            .children
             .filter { it.elementType == VALUE_PARAMETER }
             .forEach { wrapValueParameter(it, emit) }
         parameterList
@@ -266,7 +265,7 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         require(valueParameter.elementType == VALUE_PARAMETER)
-        if (valueParameter.prevLeaf.isWhiteSpaceWithoutNewline20) {
+        if (valueParameter.prevLeaf.isWhiteSpaceWithoutNewline) {
             emit(valueParameter.startOffset, "Newline expected before parameter", true)
                 .ifAutocorrectAllowed {
                     valueParameter.upsertWhitespaceBeforeMe(
@@ -291,7 +290,7 @@
         require(arrow.elementType == ARROW)
         arrow
             .prevLeaf
-            .takeIf { it.isWhiteSpaceWithoutNewline20 }
+            .takeIf { it.isWhiteSpaceWithoutNewline }
             ?.let {
                 emit(arrow.startOffset, "Newline expected before arrow", true)
                     .ifAutocorrectAllowed {
@@ -339,7 +338,7 @@
         require(parameterList.elementType == VALUE_PARAMETER_LIST)
         parameterList
             .takeUnless { it.isPrecededByComment() }
-            ?.prevSibling { it.isWhiteSpaceWithNewline20 }
+            ?.prevSibling { it.isWhiteSpaceWithNewline }
             ?.let { whitespaceBeforeParameterList ->
                 emit(parameterList.startOffset, "No newline expected before parameter", true)
                     .ifAutocorrectAllowed {
@@ -347,8 +346,8 @@
                     }
             }
         parameterList
-            .nextSibling { it.isWhiteSpace20 }
-            ?.takeIf { it.isWhiteSpaceWithNewline20 }
+            .nextSibling { it.isWhiteSpace }
+            ?.takeIf { it.isWhiteSpaceWithNewline }
             ?.let { whitespaceAfterParameterList ->
                 emit(parameterList.startOffset + parameterList.textLength, "No newline expected after parameter", true)
                     .ifAutocorrectAllowed {
@@ -357,7 +356,7 @@
             }
     }
 
-    private fun ASTNode.isPrecededByComment() = siblings(forward = false).any { it.isPartOfComment20 }
+    private fun ASTNode.isPrecededByComment() = siblings(forward = false).any { it.isPartOfComment }
 
     private fun visitArrow(
         arrow: ASTNode,
@@ -373,8 +372,8 @@
                 emit(arrow.startOffset, "Arrow is redundant when parameter list is empty", true)
                     .ifAutocorrectAllowed {
                         arrow
-                            .nextSibling20
-                            .takeIf { it.isWhiteSpace20 }
+                            .nextSibling
+                            .takeIf { it.isWhiteSpace }
                             ?.remove()
                         arrow.remove()
                     }
@@ -416,7 +415,7 @@
         require(block.elementType == BLOCK)
         if (block.textContains('\n') || block.exceedsMaxLineLength()) {
             block
-                .prevCodeSibling20
+                .prevCodeSibling
                 ?.let { prevCodeSibling ->
                     when (prevCodeSibling.elementType) {
                         ARROW -> wrapAfterArrow(prevCodeSibling, emit)
@@ -426,7 +425,7 @@
                 }
 
             block
-                .nextCodeSibling20
+                .nextCodeSibling
                 ?.takeIf { it.elementType == RBRACE }
                 ?.let { rbrace -> wrapBeforeRbrace(rbrace, emit) }
         }
@@ -439,7 +438,7 @@
         require(lbrace.elementType == LBRACE)
         lbrace
             .nextLeaf
-            .takeIf { it.isWhiteSpace20 }
+            .takeIf { it.isWhiteSpace }
             .let { whitespaceAfterLbrace ->
                 if (whitespaceAfterLbrace.isWhiteSpaceWithoutNewlineOrNull) {
                     emit(lbrace.startOffset, "Newline expected after opening brace", true)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionNamingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionNamingRule.kt
index 82bc0c3..87955a2 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionNamingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionNamingRule.kt
@@ -19,11 +19,11 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CommaSeparatedListValueParser
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfigProperty
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import com.pinterest.ktlint.ruleset.standard.rules.internal.regExIgnoringDiacriticsAndStrokesOnLetters
 import org.ec4j.core.model.PropertyType
@@ -129,7 +129,7 @@
     private fun ASTNode.isAnonymousFunction() =
         VALUE_PARAMETER_LIST ==
             findChildByType(FUN_KEYWORD)
-                ?.nextCodeSibling20
+                ?.nextCodeSibling
                 ?.elementType
 
     /*
@@ -139,7 +139,7 @@
      */
     private fun ASTNode.isOverrideFunction() =
         findChildByType(MODIFIER_LIST)
-            ?.children20
+            ?.children
             .orEmpty()
             .any { it.elementType == OVERRIDE_KEYWORD }
 
@@ -148,7 +148,7 @@
 
     private fun ASTNode?.containsAnnotationEntryWithIdentifierIn(excludeWhenAnnotatedWith: Set<String>): Boolean =
         this
-            ?.children20
+            ?.children
             ?.any {
                 when (it.elementType) {
                     ANNOTATION -> {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionReturnTypeSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionReturnTypeSpacingRule.kt
index 603d5ac..a00d7ea 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionReturnTypeSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionReturnTypeSpacingRule.kt
@@ -10,8 +10,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -54,7 +54,7 @@
         require(node.elementType == COLON)
         node
             .prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.let { whitespaceBeforeColonNode ->
                 emit(whitespaceBeforeColonNode.startOffset, "Unexpected whitespace", true)
                     .ifAutocorrectAllowed { whitespaceBeforeColonNode.remove() }
@@ -68,7 +68,7 @@
         require(node.elementType == COLON)
         node
             .nextLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             .let { whiteSpaceAfterColon ->
                 if (whiteSpaceAfterColon?.text != " ") {
                     // In case the whitespace contains a newline than replacing it with a single space results in merging the lines to a
@@ -100,7 +100,7 @@
             0
         } else {
             leaves(forward = forward)
-                .takeWhile { !it.isWhiteSpaceWithNewline20 }
+                .takeWhile { !it.isWhiteSpaceWithNewline }
                 .sumOf { it.textLength }
         }
 }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionSignatureRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionSignatureRule.kt
index 0c94138..3b8eb5d 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionSignatureRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionSignatureRule.kt
@@ -25,7 +25,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CodeStyleValue.ktlint_official
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
@@ -34,23 +34,23 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY_OFF
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isLeaf20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isLeaf
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewlineOrNull
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
@@ -123,7 +123,7 @@
         //     fun foo(bar: String) {
         // or
         //     fun foo(bar: String) =
-        val firstCodeChild = getFirstCodeChild()?.firstChildLeafOrSelf20
+        val firstCodeChild = getFirstCodeChild()?.firstChildLeafOrSelf
         val startOfBodyBlock =
             this
                 .findChildByType(BLOCK)
@@ -146,16 +146,16 @@
         funNode
             ?.findChildByType(MODIFIER_LIST)
             ?.let { modifierList ->
-                val iterator = modifierList.children20.iterator()
+                val iterator = modifierList.children.iterator()
                 var currentNode: ASTNode
                 while (iterator.hasNext()) {
                     currentNode = iterator.next()
                     if (currentNode.elementType == CONTEXT_RECEIVER_LIST) {
                         return currentNode
-                            .lastChildLeafOrSelf20
+                            .lastChildLeafOrSelf
                             .nextLeaf
                             .let { leafAfterCompositeContextReceiverList ->
-                                if (leafAfterCompositeContextReceiverList.isWhiteSpaceWithNewline20) {
+                                if (leafAfterCompositeContextReceiverList.isWhiteSpaceWithNewline) {
                                     // Ignore context receiver when followed by newline or EOL comment. Also, ignore that newline or EOL
                                     // comment.
                                     //     context(Foo)
@@ -176,7 +176,7 @@
                         return currentNode
                     }
                 }
-                return modifierList.nextCodeSibling20
+                return modifierList.nextCodeSibling
             }
 
         return funNode?.nextCodeLeaf
@@ -259,21 +259,21 @@
 
     private fun ASTNode.containsMultilineParameter(): Boolean =
         findChildByType(VALUE_PARAMETER_LIST)
-            ?.children20
+            ?.children
             .orEmpty()
             .filter { it.elementType == VALUE_PARAMETER }
             .any { it.textContains('\n') }
 
     private fun ASTNode.containsAnnotatedParameter(): Boolean =
         findChildByType(VALUE_PARAMETER_LIST)
-            ?.children20
+            ?.children
             .orEmpty()
             .filter { it.elementType == VALUE_PARAMETER }
             .any { it.isAnnotated() }
 
     private fun ASTNode.isAnnotated() =
         findChildByType(MODIFIER_LIST)
-            ?.children20
+            ?.children
             .orEmpty()
             .any { it.elementType == ANNOTATION_ENTRY }
 
@@ -313,7 +313,7 @@
         val valueParameterList = requireNotNull(node.findChildByType(VALUE_PARAMETER_LIST))
         val firstParameterInList =
             valueParameterList
-                .children20
+                .children
                 .firstOrNull { it.elementType == VALUE_PARAMETER }
 
         whiteSpaceCorrection +=
@@ -339,7 +339,7 @@
         val valueParameterList = requireNotNull(node.findChildByType(VALUE_PARAMETER_LIST))
 
         valueParameterList
-            .children20
+            .children
             .filter { it.elementType != LPAR && it.elementType != RPAR }
             .also { elementsInValueParameterList ->
                 // Functions with comments in the value parameter list are excluded from processing before. So an "empty" value
@@ -372,13 +372,13 @@
         val valueParameterList = requireNotNull(node.findChildByType(VALUE_PARAMETER_LIST))
         val firstParameterInList =
             valueParameterList
-                .children20
+                .children
                 .first { it.elementType == VALUE_PARAMETER }
 
         val firstParameter = firstParameterInList.firstChildNode
         firstParameter
             ?.prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             .let { whiteSpaceBeforeIdentifier ->
                 if (multiline) {
                     val expectedParameterIndent = indentConfig.childIndentOf(node)
@@ -426,18 +426,18 @@
         val valueParameterList = requireNotNull(node.findChildByType(VALUE_PARAMETER_LIST))
         val firstParameterInList =
             valueParameterList
-                .children20
+                .children
                 .first { it.elementType == VALUE_PARAMETER }
 
         valueParameterList
-            .children20
+            .children
             .filter { it.elementType == VALUE_PARAMETER }
             .filter { it != firstParameterInList }
             .forEach { valueParameter ->
                 val firstChildNodeInValueParameter = valueParameter.firstChildNode
                 firstChildNodeInValueParameter
                     ?.prevLeaf
-                    ?.takeIf { it.isWhiteSpace20 }
+                    ?.takeIf { it.isWhiteSpace }
                     .let { whiteSpaceBeforeIdentifier ->
                         if (multiline) {
                             val expectedParameterIndent = indentConfig.childIndentOf(node)
@@ -485,13 +485,13 @@
     ): Int {
         var whiteSpaceCorrection = 0
 
-        val newlineAndIndent = node.indent20
+        val newlineAndIndent = node.indent
         val valueParameterList = requireNotNull(node.findChildByType(VALUE_PARAMETER_LIST))
 
         val closingParenthesis = valueParameterList.findChildByType(RPAR)
         closingParenthesis
-            ?.prevSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.prevSibling
+            ?.takeIf { it.isWhiteSpace }
             .let { whiteSpaceBeforeClosingParenthesis ->
                 if (multiline) {
                     if (whiteSpaceBeforeClosingParenthesis == null ||
@@ -540,7 +540,7 @@
                 ?: return
         val bodyNodes = node.getFunctionBody(lastNodeOfFunctionSignatureWithBodyExpression)
         val whiteSpaceBeforeFunctionBodyExpression = bodyNodes.getStartingWhitespaceOrNull()
-        val functionBodyExpressionNodes = bodyNodes.dropWhile { it.isWhiteSpace20 }
+        val functionBodyExpressionNodes = bodyNodes.dropWhile { it.isWhiteSpace }
 
         val functionBodyExpressionLines =
             functionBodyExpressionNodes
@@ -549,9 +549,9 @@
         functionBodyExpressionLines
             .firstOrNull()
             ?.also { firstLineOfBodyExpression ->
-                if (whiteSpaceBeforeFunctionBodyExpression.isWhiteSpaceWithNewline20) {
+                if (whiteSpaceBeforeFunctionBodyExpression.isWhiteSpaceWithNewline) {
                     lastNodeOfFunctionSignatureWithBodyExpression
-                        .nextCodeSibling20
+                        .nextCodeSibling
                         .takeIf { it?.elementType == ANNOTATED_EXPRESSION }
                         ?.let {
                             // Never merge an annotated expression body with function signature as this conflicts with the Annotation rule
@@ -657,7 +657,7 @@
             ?.let { block ->
                 block
                     .prevLeaf
-                    .takeIf { it.isWhiteSpace20 }
+                    .takeIf { it.isWhiteSpace }
                     .let { whiteSpaceBeforeBlock ->
                         if (whiteSpaceBeforeBlock == null || whiteSpaceBeforeBlock.text != " ") {
                             if (!dryRun) {
@@ -689,17 +689,17 @@
     private fun List<ASTNode>.getStartingWhitespaceOrNull() =
         this
             .firstOrNull()
-            ?.takeIf { first -> first.isWhiteSpace20 }
+            ?.takeIf { first -> first.isWhiteSpace }
 
     private fun isMaxLineLengthSet() = maxLineLength != MAX_LINE_LENGTH_PROPERTY_OFF
 
     private fun List<ASTNode>.collectLeavesRecursively(): List<ASTNode> = flatMap { it.collectLeavesRecursively() }
 
     private fun ASTNode.collectLeavesRecursively(): List<ASTNode> =
-        if (isLeaf20) {
+        if (isLeaf) {
             listOf(this)
         } else {
-            children20
+            children
                 .flatMap { it.collectLeavesRecursively() }
                 .toList()
         }
@@ -739,7 +739,7 @@
     private fun ASTNode.countParameters(): Int {
         val valueParameterList = requireNotNull(findChildByType(VALUE_PARAMETER_LIST))
         return valueParameterList
-            .children20
+            .children
             .count { it.elementType == VALUE_PARAMETER }
     }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionStartOfBodySpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionStartOfBodySpacingRule.kt
index 05bbe97..5d7e7ee 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionStartOfBodySpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionStartOfBodySpacingRule.kt
@@ -10,7 +10,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
@@ -88,7 +88,7 @@
                     .nextLeaf
                     ?.takeIf { it.elementType == WHITE_SPACE }
                     .let { whiteSpaceAfterAssignment ->
-                        if (whiteSpaceAfterAssignment?.text != " " && !whiteSpaceAfterAssignment.isWhiteSpaceWithNewline20) {
+                        if (whiteSpaceAfterAssignment?.text != " " && !whiteSpaceAfterAssignment.isWhiteSpaceWithNewline) {
                             emit(
                                 assignmentExpression.startOffset,
                                 "Expected a single white space between assignment and expression body on same line",
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeModifierSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeModifierSpacingRule.kt
index 0c0772b..767f86e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeModifierSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeModifierSpacingRule.kt
@@ -8,9 +8,9 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -27,7 +27,7 @@
     ) {
         node
             .takeIf { it.elementType == MODIFIER_LIST }
-            ?.nextCodeSibling20
+            ?.nextCodeSibling
             ?.takeIf { it.elementType == FUNCTION_TYPE }
             ?.takeUnless { it.isPrecededBySingleSpace() }
             ?.let { functionTypeNode ->
@@ -39,8 +39,8 @@
     }
 
     private fun ASTNode.isPrecededBySingleSpace(): Boolean =
-        prevSibling20
-            ?.let { it.isWhiteSpace20 && it.text == " " }
+        prevSibling
+            ?.let { it.isWhiteSpace && it.text == " " }
             ?: false
 }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeReferenceSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeReferenceSpacingRule.kt
index 1eeb6c9..e65d127 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeReferenceSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/FunctionTypeReferenceSpacingRule.kt
@@ -10,8 +10,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -48,7 +48,7 @@
             if (currentNode.elementType == TYPE_REFERENCE) {
                 return currentNode
             }
-            currentNode = currentNode.nextSibling20
+            currentNode = currentNode.nextSibling
         }
         return null
     }
@@ -59,7 +59,7 @@
     ) {
         var currentNode: ASTNode? = node
         while (currentNode != null && currentNode.elementType != VALUE_PARAMETER_LIST) {
-            val nextNode = currentNode.nextSibling20
+            val nextNode = currentNode.nextSibling
             removeIfNonEmptyWhiteSpace(currentNode, emit)
             currentNode = nextNode
         }
@@ -69,7 +69,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isWhiteSpace20 && node.text.isNotEmpty()) {
+        if (node.isWhiteSpace && node.text.isNotEmpty()) {
             emit(node.startOffset, "Unexpected whitespace", true)
                 .ifAutocorrectAllowed { node.remove() }
         }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseBracingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseBracingRule.kt
index d2c8035..663d3ed 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseBracingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseBracingRule.kt
@@ -19,10 +19,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
@@ -144,13 +144,13 @@
         val nextLeaves =
             node
                 .leaves(forward = true)
-                .takeWhile { it.isWhiteSpaceWithoutNewline20 || it.isPartOfComment20 }
+                .takeWhile { it.isWhiteSpaceWithoutNewline || it.isPartOfComment }
                 .toList()
-                .dropLastWhile { it.isWhiteSpaceWithoutNewline20 }
+                .dropLastWhile { it.isWhiteSpaceWithoutNewline }
 
         prevLeaves
             .firstOrNull()
-            .takeIf { it.isWhiteSpace20 }
+            .takeIf { it.isWhiteSpace }
             ?.replaceTextWith(" ")
         KtBlockExpression(null).apply {
             val previousChild = node.firstChildNode
@@ -164,7 +164,7 @@
                 addChild(PsiWhiteSpaceImpl(indentConfig.childIndentOf(node)))
             }
             prevLeaves
-                .dropWhile { it.isWhiteSpace20 }
+                .dropWhile { it.isWhiteSpace }
                 .takeIf { it.isNotEmpty() }
                 ?.forEach(::addChild)
             if (previousChild != null) {
@@ -172,7 +172,7 @@
             }
             nextLeaves.forEach(::addChild)
             if (previousChild != null) {
-                addChild(PsiWhiteSpaceImpl(node.indent20))
+                addChild(PsiWhiteSpaceImpl(node.indent))
             }
             addChild(LeafPsiElement(RBRACE, "}"))
         }
@@ -180,7 +180,7 @@
         // Make sure else starts on same line as newly inserted right brace
         if (node.elementType == THEN) {
             node
-                .nextSibling { !it.isPartOfComment20 }
+                .nextSibling { !it.isPartOfComment }
                 ?.upsertWhitespaceBeforeMe(" ")
         }
     }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseWrappingRule.kt
index f864a5c..4943a11 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IfElseWrappingRule.kt
@@ -17,18 +17,18 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.betweenCodeSiblings
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -70,7 +70,7 @@
     ) {
         when {
             node.elementType == IF -> visitIf(node, emit)
-            node.isPartOfComment20 && node.parent?.elementType == IF -> visitComment(node, emit)
+            node.isPartOfComment && node.parent?.elementType == IF -> visitComment(node, emit)
         }
     }
 
@@ -146,14 +146,14 @@
 
         with(node.findFirstNodeInBlockToBeIndented() ?: node) {
             val expectedIndent =
-                if (nextSibling20?.elementType == RBRACE) {
-                    node.indent20
+                if (nextSibling?.elementType == RBRACE) {
+                    node.indent
                 } else {
                     indentConfig.siblingIndentOf(node)
                 }
 
             applyIf(elementType == THEN || elementType == ELSE || elementType == ELSE_KEYWORD) { prevLeaf!! }
-                .takeUnless { it.isWhiteSpaceWithNewline20 }
+                .takeUnless { it.isWhiteSpaceWithNewline }
                 ?.let {
                     // Expected a newline with indent. Leave it up to the IndentationRule to determine exact indent
                     emit(startOffset, "Expected a newline", true)
@@ -173,14 +173,14 @@
 
     private fun ASTNode.findFirstNodeInBlockToBeIndented(): ASTNode? =
         findChildByType(BLOCK)
-            ?.children20
+            ?.children
             ?.first {
                 it.elementType != LBRACE &&
                     !it.isWhitespaceBeforeComment() &&
-                    !it.isPartOfComment20
+                    !it.isPartOfComment
             }
 
-    private fun ASTNode.isWhitespaceBeforeComment() = isWhiteSpaceWithoutNewline20 && nextLeaf?.isPartOfComment20 == true
+    private fun ASTNode.isWhitespaceBeforeComment() = isWhiteSpaceWithoutNewline && nextLeaf?.isPartOfComment == true
 
     private fun ASTNode.outerIf(): ASTNode {
         require(this.elementType == IF)
@@ -200,7 +200,7 @@
         comment: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        require(comment.isPartOfComment20)
+        require(comment.isPartOfComment)
         if (comment.betweenCodeSiblings(RPAR, THEN) ||
             comment.betweenCodeSiblings(THEN, ELSE_KEYWORD) ||
             comment.betweenCodeSiblings(ELSE_KEYWORD, ELSE)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ImportOrderingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ImportOrderingRule.kt
index 9662362..eed7aa4 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ImportOrderingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ImportOrderingRule.kt
@@ -12,9 +12,9 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfigProperty
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import com.pinterest.ktlint.ruleset.standard.rules.ImportOrderingRule.Companion.ASCII_PATTERN
 import com.pinterest.ktlint.ruleset.standard.rules.ImportOrderingRule.Companion.IDEA_PATTERN
@@ -124,10 +124,10 @@
                         ).ifAutocorrectAllowed { autocorrect = true }
                     }
                     if (autocorrect) {
-                        node.removeRange(node.firstChildNode, node.lastChildNode.nextSibling20)
+                        node.removeRange(node.firstChildNode, node.lastChildNode.nextSibling)
                         sortedImportsWithSpaces.reduce { current, next ->
                             node.addChild(current, null)
-                            if (!current.isWhiteSpace20 && !next.isWhiteSpace20) {
+                            if (!current.isWhiteSpace && !next.isWhiteSpace) {
                                 node.addChild(PsiWhiteSpaceImpl("\n"), null)
                             }
                             return@reduce next
@@ -149,7 +149,7 @@
 
         children.forEach { current ->
             when {
-                current.isWhiteSpace20 && current.text.count { it == '\n' } > 1 -> {
+                current.isWhiteSpace && current.text.count { it == '\n' } > 1 -> {
                     imports += current
                 }
 
@@ -175,7 +175,7 @@
 
         val combined = actual.zip(expected)
         return combined.all { (first, second) ->
-            if (first.isWhiteSpace20 && second.isWhiteSpace20) {
+            if (first.isWhiteSpace && second.isWhiteSpace) {
                 return@all (first as PsiWhiteSpace).text == (second as PsiWhiteSpace).text
             }
             return@all first == second
@@ -184,7 +184,7 @@
 
     private fun isCustomLayout() = importsLayout != IDEA_PATTERN && importsLayout != ASCII_PATTERN
 
-    private fun hasTooMuchWhitespace(nodes: Array<ASTNode>): Boolean = nodes.any { it.isWhiteSpaceWithoutNewline20 }
+    private fun hasTooMuchWhitespace(nodes: Array<ASTNode>): Boolean = nodes.any { it.isWhiteSpaceWithoutNewline }
 
     public companion object {
         /**
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IndentationRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IndentationRule.kt
index 91f9826..996795b 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IndentationRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/IndentationRule.kt
@@ -88,7 +88,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.TokenSets
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.column
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CODE_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.CodeStyleValue
@@ -98,24 +98,24 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.findParentByType
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
 import com.pinterest.ktlint.rule.engine.core.api.isCode
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isRoot20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isRoot
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -172,11 +172,11 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isRoot20) {
+        if (node.isRoot) {
             // File should not start with a whitespace
             node
                 .nextLeaf
-                ?.takeIf { it.isWhiteSpaceWithoutNewline20 }
+                ?.takeIf { it.isWhiteSpaceWithoutNewline }
                 ?.let { whitespaceWithoutNewline ->
                     emit(node.startOffset, "Unexpected indentation", true)
                         .ifAutocorrectAllowed { whitespaceWithoutNewline.remove() }
@@ -185,7 +185,7 @@
         }
 
         when {
-            node.isWhiteSpaceWithNewline20 -> {
+            node.isWhiteSpaceWithNewline -> {
                 line++
                 if (indentContextStack.peekLast()?.activated == false) {
                     val lastIndentContext = indentContextStack.removeLast()
@@ -207,10 +207,10 @@
             }
 
             (node.elementType == SUPER_TYPE_LIST && !node.isPrecededByComment()) ||
-                (node.isPartOfComment20 && node.nextCodeSibling20?.elementType == SUPER_TYPE_LIST) -> {
+                (node.isPartOfComment && node.nextCodeSibling?.elementType == SUPER_TYPE_LIST) -> {
                 if (codeStyle == ktlint_official) {
                     val superTypeList =
-                        if (node.isPartOfComment20) {
+                        if (node.isPartOfComment) {
                             node.nextCodeLeaf!!
                         } else {
                             node
@@ -304,7 +304,7 @@
             }
 
             node.elementType == LPAR &&
-                node.nextCodeSibling20?.elementType == CONDITION -> {
+                node.nextCodeSibling?.elementType == CONDITION -> {
                 visitLparBeforeCondition(node)
             }
 
@@ -341,9 +341,9 @@
                     //    }
                     startIndentContext(
                         fromAstNode = node.parent!!,
-                        toAstNode = node.parent!!.parent!!.lastChildLeafOrSelf20,
+                        toAstNode = node.parent!!.parent!!.lastChildLeafOrSelf,
                     )
-                } else if (node.prevCodeSibling20.isElvisOperator()) {
+                } else if (node.prevCodeSibling.isElvisOperator()) {
                     startIndentContext(node)
                 } else if (node.parent?.elementType in CHAINABLE_EXPRESSION) {
                     // Multiple dot qualified expressions and/or safe expression on the same line should not increase the indent level
@@ -358,7 +358,7 @@
             }
 
             node.elementType == LITERAL_STRING_TEMPLATE_ENTRY &&
-                node.nextCodeSibling20?.elementType == CLOSING_QUOTE -> {
+                node.nextCodeSibling?.elementType == CLOSING_QUOTE -> {
                 visitWhiteSpaceBeforeClosingQuote(node, emit)
             }
 
@@ -371,7 +371,7 @@
             }
 
             node.elementType == WHERE_KEYWORD &&
-                node.nextCodeSibling20?.elementType == TYPE_CONSTRAINT_LIST -> {
+                node.nextCodeSibling?.elementType == TYPE_CONSTRAINT_LIST -> {
                 visitWhereKeywordBeforeTypeConstraintList(node)
             }
 
@@ -455,7 +455,7 @@
     }
 
     private fun visitIf(node: ASTNode) {
-        var nextToAstNode = node.lastChildLeafOrSelf20
+        var nextToAstNode = node.lastChildLeafOrSelf
         node
             .findChildByType(ELSE)
             ?.let { fromAstNode ->
@@ -468,7 +468,7 @@
 
         node
             .findChildByType(THEN)
-            ?.lastChildLeafOrSelf20
+            ?.lastChildLeafOrSelf
             ?.nextLeaf
             ?.let { nodeAfterThenBlock ->
                 nextToAstNode =
@@ -565,7 +565,7 @@
                 .takeIf { it.isPartOf(CALL_EXPRESSION) }
                 ?.parent
                 ?.leaves(false)
-                ?.takeWhile { !it.isWhiteSpaceWithNewline20 }
+                ?.takeWhile { !it.isWhiteSpaceWithNewline }
                 ?.sumOf { it.textLength }
                 ?.plus(2) // need to add spaces to compensate for "{ "
                 ?.let { length -> " ".repeat(length) }
@@ -582,7 +582,7 @@
             // Allow to pickup whitespace before condition
             fromAstNode = requireNotNull(node.nextLeaf),
             // Ignore whitespace after condition but before rpar
-            toAstNode = requireNotNull(node.nextCodeSibling20).lastChildLeafOrSelf20,
+            toAstNode = requireNotNull(node.nextCodeSibling).lastChildLeafOrSelf,
             nodeIndent = currentIndent() + indentConfig.indent,
             childIndent = "",
         )
@@ -590,7 +590,7 @@
 
     private fun visitValueParameter(node: ASTNode) {
         // Inner indent contexts in reversed order
-        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf20
+        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf
         node
             .findChildByType(EQ)
             ?.let { fromAstNode ->
@@ -621,13 +621,13 @@
         // Leading annotations and comments should be indented at same level as constructor itself
         val fromAstNode = node.skipLeadingWhitespaceCommentsAndAnnotations()
         if (fromAstNode != node.firstChildNode &&
-            node.prevSibling { it.isWhiteSpaceWithNewline20 } == null &&
+            node.prevSibling { it.isWhiteSpaceWithNewline } == null &&
             node == node.parent?.findChildByType(VALUE_PARAMETER)
         ) {
             startIndentContext(
                 fromAstNode = fromAstNode,
                 toAstNode = nextToAstNode,
-            ).fromASTNode.prevLeaf { !it.isWhiteSpace20 }!!
+            ).fromASTNode.prevLeaf { !it.isWhiteSpace }!!
         } else {
             startIndentContext(
                 fromAstNode = node,
@@ -639,7 +639,7 @@
 
     private fun visitFun(node: ASTNode) {
         // Inner indent contexts in reversed order
-        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf20
+        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf
         val eqOrBlock =
             node.findChildByType(EQ)
                 ?: node.findChildByType(BLOCK)
@@ -656,7 +656,7 @@
             ?.let { where ->
                 val typeConstraintList =
                     requireNotNull(
-                        where.nextCodeSibling20,
+                        where.nextCodeSibling,
                     ) { "Can not find code sibling after WHERE in FUN" }
                 require(typeConstraintList.elementType == TYPE_CONSTRAINT_LIST) {
                     "Code sibling after WHERE in CLASS is not a TYPE_CONSTRAINT_LIST"
@@ -664,7 +664,7 @@
                 nextToAstNode =
                     startIndentContext(
                         fromAstNode = where.getPrecedingLeadingCommentsAndWhitespaces(),
-                        toAstNode = typeConstraintList.lastChildLeafOrSelf20,
+                        toAstNode = typeConstraintList.lastChildLeafOrSelf,
                         childIndent =
                             " ".repeat(
                                 maxOf(0, where.column - 1 - node.indentWithoutNewlinePrefix.length),
@@ -692,13 +692,13 @@
 
     private fun visitClass(node: ASTNode) {
         // Inner indent contexts in reversed order
-        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf20
+        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf
         node
             .findChildByType(WHERE_KEYWORD)
             ?.let { where ->
                 val typeConstraintList =
                     requireNotNull(
-                        where.nextCodeSibling20,
+                        where.nextCodeSibling,
                     ) { "Can not find code sibling after WHERE in CLASS" }
                 require(typeConstraintList.elementType == TYPE_CONSTRAINT_LIST) {
                     "Code sibling after WHERE in CLASS is not a TYPE_CONSTRAINT_LIST"
@@ -706,7 +706,7 @@
                 nextToAstNode =
                     startIndentContext(
                         fromAstNode = where.getPrecedingLeadingCommentsAndWhitespaces(),
-                        toAstNode = typeConstraintList.lastChildLeafOrSelf20,
+                        toAstNode = typeConstraintList.lastChildLeafOrSelf,
                     ).prevCodeLeaf()
             }
 
@@ -726,7 +726,7 @@
                     nextToAstNode =
                         startIndentContext(
                             fromAstNode = superTypeList.getPrecedingLeadingCommentsAndWhitespaces(),
-                            toAstNode = superTypeList.lastChildLeafOrSelf20,
+                            toAstNode = superTypeList.lastChildLeafOrSelf,
                         ).prevCodeLeaf()
                 }
         }
@@ -741,14 +741,14 @@
 
     private fun visitObjectDeclaration(node: ASTNode) {
         // Inner indent contexts in reversed order
-        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf20
+        var nextToAstNode: ASTNode = node.lastChildLeafOrSelf
         node
             .findChildByType(SUPER_TYPE_LIST)
             ?.let { superTypeList ->
                 nextToAstNode =
                     startIndentContext(
                         fromAstNode = superTypeList.getPrecedingLeadingCommentsAndWhitespaces(),
-                        toAstNode = superTypeList.lastChildLeafOrSelf20,
+                        toAstNode = superTypeList.lastChildLeafOrSelf,
                     ).prevCodeLeaf()
             }
 
@@ -769,7 +769,7 @@
             // Create new indent context for the remainder (operator and right-hand side) of the binary expression
             startIndentContext(
                 fromAstNode = node.findChildByType(OPERATION_REFERENCE)!!,
-                toAstNode = node.lastChildLeafOrSelf20,
+                toAstNode = node.lastChildLeafOrSelf,
                 nodeIndent = conditionIndentContext.nodeIndent,
                 childIndent = conditionIndentContext.childIndent,
             )
@@ -784,12 +784,12 @@
     private fun visitIdentifierInProperty(node: ASTNode) {
         startIndentContext(
             fromAstNode = node,
-            toAstNode = node.parent!!.lastChildLeafOrSelf20,
+            toAstNode = node.parent!!.lastChildLeafOrSelf,
         )
     }
 
     private fun visitWhen(node: ASTNode) {
-        var nextToASTNode = node.lastChildLeafOrSelf20
+        var nextToASTNode = node.lastChildLeafOrSelf
         node
             .findChildByType(LPAR)
             ?.let { lpar ->
@@ -811,10 +811,10 @@
             .findChildByType(ARROW)
             ?.let { arrow ->
                 arrow
-                    .prevSibling { !it.isPartOfComment20 }
+                    .prevSibling { !it.isPartOfComment }
                     .let { prevSibling ->
-                        if (indentWhenArrowOnNewLine && prevSibling != null && prevSibling.isWhiteSpaceWithNewline20) {
-                            if (arrow.nextCodeSibling20?.elementType == BLOCK && codeStyle != ktlint_official) {
+                        if (indentWhenArrowOnNewLine && prevSibling != null && prevSibling.isWhiteSpaceWithNewline) {
+                            if (arrow.nextCodeSibling?.elementType == BLOCK && codeStyle != ktlint_official) {
                                 // Uglify the indentation to below to keep compatible with default formatting Intellij IDEA
                                 //     val foo =
                                 //        when (bar()) {
@@ -825,7 +825,7 @@
                                 //        }
                                 startIndentContext(
                                     fromAstNode = prevSibling,
-                                    toAstNode = node.lastChildLeafOrSelf20,
+                                    toAstNode = node.lastChildLeafOrSelf,
                                     firstChildIndent = indentConfig.indent,
                                     childIndent = "",
                                 )
@@ -841,7 +841,7 @@
                                 //        }
                                 startIndentContext(
                                     fromAstNode = arrow.nextLeaf!!,
-                                    toAstNode = node.lastChildLeafOrSelf20,
+                                    toAstNode = node.lastChildLeafOrSelf,
                                 )
                                 startIndentContext(
                                     fromAstNode = node,
@@ -852,7 +852,7 @@
                         } else {
                             startIndentContext(
                                 fromAstNode = arrow.nextLeaf!!,
-                                toAstNode = node.lastChildLeafOrSelf20,
+                                toAstNode = node.lastChildLeafOrSelf,
                             )
                             startIndentContext(
                                 fromAstNode = node,
@@ -867,7 +867,7 @@
     private fun visitWhereKeywordBeforeTypeConstraintList(node: ASTNode) {
         node
             .prevLeaf
-            .takeUnless { it.isWhiteSpaceWithNewline20 }
+            .takeUnless { it.isWhiteSpaceWithNewline }
             ?.takeIf { !indentContextStack.peekLast().activated }
             ?.let {
                 val lastIndentContext = indentContextStack.removeLast()
@@ -878,7 +878,7 @@
 
         startIndentContext(
             fromAstNode = node,
-            toAstNode = node.nextCodeSibling20?.lastChildLeafOrSelf20!!,
+            toAstNode = node.nextCodeSibling?.lastChildLeafOrSelf!!,
             childIndent = TYPE_CONSTRAINT_CONTINUATION_INDENT,
         )
     }
@@ -890,21 +890,21 @@
             ?.let { fromAstNode ->
                 startIndentContext(
                     fromAstNode = fromAstNode,
-                    toAstNode = node.lastChildLeafOrSelf20,
+                    toAstNode = node.lastChildLeafOrSelf,
                     childIndent = KDOC_CONTINUATION_INDENT,
                 )
             }
     }
 
     private fun visitPropertyAccessor(node: ASTNode) {
-        var nextToASTNode = node.lastChildLeafOrSelf20
+        var nextToASTNode = node.lastChildLeafOrSelf
         node
             .findChildByType(EQ)
             ?.let { fromAstNode ->
                 nextToASTNode =
                     startIndentContext(
                         fromAstNode = fromAstNode,
-                        toAstNode = node.lastChildLeafOrSelf20,
+                        toAstNode = node.lastChildLeafOrSelf,
                     ).prevCodeLeaf()
             }
         // No indent on preceding annotations and comments
@@ -923,7 +923,7 @@
             ?.let { rpar ->
                 startIndentContext(
                     fromAstNode = rpar,
-                    toAstNode = node.lastChildLeafOrSelf20,
+                    toAstNode = node.lastChildLeafOrSelf,
                 )
             }
         node
@@ -953,7 +953,7 @@
 
     private fun visitNullableType(node: ASTNode) {
         // Inner indent contexts in reversed order
-        var nextToAstNode = node.lastChildLeafOrSelf20
+        var nextToAstNode = node.lastChildLeafOrSelf
         node
             .findChildByType(RPAR)
             ?.let { fromAstNode ->
@@ -972,7 +972,7 @@
 
     private fun visitDestructuringDeclaration(node: ASTNode) {
         // Inner indent contexts in reversed order
-        var nextToAstNode = node.lastChildLeafOrSelf20
+        var nextToAstNode = node.lastChildLeafOrSelf
         node
             .findChildByType(EQ)
             ?.let { eq ->
@@ -996,7 +996,7 @@
 
     private fun visitTryCatchFinally(node: ASTNode) {
         // Inner indent contexts in reversed order
-        var nextToAstNode = node.lastChildLeafOrSelf20
+        var nextToAstNode = node.lastChildLeafOrSelf
         node
             .findChildByType(FINALLY)
             ?.let { finally ->
@@ -1031,18 +1031,18 @@
         return findChildByType(MODIFIER_LIST)
             ?.let { modifierList ->
                 modifierList
-                    .children20
+                    .children
                     .firstOrNull { it.isCode && it.elementType != ANNOTATION_ENTRY }
-                    ?: modifierList.nextCodeSibling20
+                    ?: modifierList.nextCodeSibling
             }
-            ?: children20.firstOrNull { it.isCode }
+            ?: children.firstOrNull { it.isCode }
             ?: this
     }
 
     private fun ASTNode.getPrecedingLeadingCommentsAndWhitespaces(): ASTNode {
         var fromAstNode: ASTNode? = this
         while (fromAstNode?.prevLeaf != null &&
-            (fromAstNode.prevLeaf.isWhiteSpace20 || fromAstNode.prevLeaf?.isPartOfComment20 == true)
+            (fromAstNode.prevLeaf.isWhiteSpace || fromAstNode.prevLeaf?.isPartOfComment == true)
         ) {
             fromAstNode = fromAstNode.prevLeaf
         }
@@ -1063,7 +1063,7 @@
 
     private fun startIndentContext(
         fromAstNode: ASTNode,
-        toAstNode: ASTNode = fromAstNode.lastChildLeafOrSelf20,
+        toAstNode: ASTNode = fromAstNode.lastChildLeafOrSelf,
         nodeIndent: String = currentIndent(),
         childIndent: String = indentConfig.indent,
         firstChildIndent: String = childIndent,
@@ -1201,8 +1201,8 @@
         val nextLeaf = nextLeaf
         val adjustedChildIndent =
             when {
-                this == lastIndexContext.fromASTNode.firstChildLeafOrSelf20 ||
-                    nextLeaf == lastIndexContext.fromASTNode.firstChildLeafOrSelf20 -> {
+                this == lastIndexContext.fromASTNode.firstChildLeafOrSelf ||
+                    nextLeaf == lastIndexContext.fromASTNode.firstChildLeafOrSelf -> {
                     lastIndexContext.firstChildIndent
                 }
 
@@ -1274,7 +1274,7 @@
             firstChildNode?.elementType == ELVIS
 
     private fun ASTNode.acceptableTrailingSpaces(): String {
-        require(isWhiteSpace20)
+        require(isWhiteSpace)
         val acceptableTrailingSpaces =
             when (nextLeaf?.elementType) {
                 KDOC_LEADING_ASTERISK, KDOC_END -> {
@@ -1312,7 +1312,7 @@
             activated = true,
         )
 
-    private fun ASTNode.isPrecededByComment() = prevSibling { !it.isWhiteSpace20 }?.isPartOfComment20 == true
+    private fun ASTNode.isPrecededByComment() = prevSibling { !it.isWhiteSpace }?.isPartOfComment == true
 
     public companion object {
         private const val KDOC_CONTINUATION_INDENT = " "
@@ -1344,7 +1344,7 @@
          * The node at which the indent context ends. If null, then the context ends at the last child leaf of the node
          * on which the indent context starts.
          */
-        val toASTNode: ASTNode = fromASTNode.lastChildLeafOrSelf20,
+        val toASTNode: ASTNode = fromASTNode.lastChildLeafOrSelf,
         /**
          * Cumulative indentation for the node. Normally this should be equal to a multiple of the
          * 'indentConfig.indentStyle' to ensure a consistent indentation style.
@@ -1469,7 +1469,7 @@
                         expectedIndent
                     }
                 node
-                    .children20
+                    .children
                     .filter { it.isIndentBeforeClosingQuote() }
                     .forEach {
                         if (it.prevLeaf?.text == "\n") {
@@ -1495,7 +1495,7 @@
     }
 
     private fun ASTNode.isRawStringLiteralFunctionBodyExpression() =
-        (!prevLeaf.isWhiteSpace20 || prevLeaf?.text == " ") &&
+        (!prevLeaf.isWhiteSpace || prevLeaf?.text == " ") &&
             FUN ==
             prevCodeLeaf
                 .takeIf { it?.elementType == EQ }
@@ -1515,7 +1515,7 @@
             .let { it?.elementType == CALL_EXPRESSION && it.text == callExpressionName }
 
     private fun ASTNode.isMultiLine(): Boolean =
-        children20
+        children
             .filter { it.elementType == LITERAL_STRING_TEMPLATE_ENTRY }
             .any { it.text == "\n" }
 
@@ -1540,7 +1540,7 @@
     }
 
     private fun ASTNode.isIndentBeforeClosingQuote() =
-        elementType == CLOSING_QUOTE || (text.isBlank() && nextCodeSibling20?.elementType == CLOSING_QUOTE)
+        elementType == CLOSING_QUOTE || (text.isBlank() && nextCodeSibling?.elementType == CLOSING_QUOTE)
 
     private fun String.indentLength() = indexOfFirst { !it.isWhitespace() }.let { if (it == -1) length else it }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/KdocWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/KdocWrappingRule.kt
index 88b8ad9..da585b2 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/KdocWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/KdocWrappingRule.kt
@@ -11,8 +11,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
@@ -41,7 +41,7 @@
             node
                 .findChildByType(KDOC_START)
                 ?.prevLeaf
-                ?.takeIf { !it.isWhiteSpaceWithNewline20 }
+                ?.takeIf { !it.isWhiteSpaceWithNewline }
                 ?.let {
                     // It cannot be autocorrected as it might depend on the situation and code style what is
                     // preferred.
@@ -55,11 +55,11 @@
             node
                 .findChildByType(KDOC_END)
                 ?.nextLeaf
-                ?.takeIf { !it.isWhiteSpaceWithNewline20 }
+                ?.takeIf { !it.isWhiteSpaceWithNewline }
                 ?.let { nextLeaf ->
                     emit(nextLeaf.startOffset, "A KDoc comment may not be followed by any other element on that same line", true)
                         .ifAutocorrectAllowed {
-                            node.upsertWhitespaceAfterMe(node.indent20)
+                            node.upsertWhitespaceAfterMe(node.indent)
                         }
                 }
         }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MaxLineLengthRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MaxLineLengthRule.kt
index 824eeb7..80963aa 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MaxLineLengthRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MaxLineLengthRule.kt
@@ -19,10 +19,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.ktLintRuleExecutionPropertyName
 import com.pinterest.ktlint.rule.engine.core.api.findParentByType
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.lineLength
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
@@ -57,12 +57,12 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isWhiteSpace20) {
+        if (node.isWhiteSpace) {
             return
         }
         node
             .takeIf { it is LeafPsiElement }
-            ?.takeIf { it.nextLeaf == null || it.nextLeaf.isWhiteSpaceWithNewline20 }
+            ?.takeIf { it.nextLeaf == null || it.nextLeaf.isWhiteSpaceWithNewline }
             ?.takeIf { it.lineLength() > maxLineLength }
             ?.takeUnless { it.isPartOf(PACKAGE_DIRECTIVE) }
             ?.takeUnless { it.isPartOf(IMPORT_DIRECTIVE) }
@@ -75,7 +75,7 @@
                 // Calculate the offset at the last possible position at which the newline should be inserted on the line
                 val offset =
                     node
-                        .leavesOnLine20
+                        .leavesOnLine
                         .first()
                         .startOffset
                         .plus(maxLineLength + 1)
@@ -88,7 +88,7 @@
     }
 
     private fun ASTNode.lineLength() =
-        leavesOnLine20
+        leavesOnLine
             .filterNot {
                 ignoreBackTickedIdentifier &&
                     it.elementType == IDENTIFIER &&
@@ -107,14 +107,14 @@
                 stringTemplate
                     .prevLeaf
                     .let { leafBeforeStringTemplate ->
-                        leafBeforeStringTemplate == null || leafBeforeStringTemplate.isWhiteSpaceWithNewline20
+                        leafBeforeStringTemplate == null || leafBeforeStringTemplate.isWhiteSpaceWithNewline
                     }
             }
             ?: false
 
     private fun ASTNode.isLineOnlyContainingComment() =
-        isPartOfComment20 &&
-            (prevLeaf == null || prevLeaf.isWhiteSpaceWithNewline20)
+        isPartOfComment &&
+            (prevLeaf == null || prevLeaf.isWhiteSpaceWithNewline)
 
     public companion object {
         public val IGNORE_BACKTICKED_IDENTIFIER_PROPERTY: EditorConfigProperty<Boolean> =
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ModifierListSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ModifierListSpacingRule.kt
index 834b05a..039ffac 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ModifierListSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ModifierListSpacingRule.kt
@@ -11,13 +11,13 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -55,7 +55,7 @@
     ) {
         if (node.elementType == MODIFIER_LIST) {
             node
-                .children20
+                .children
                 .forEach { visitModifierChild(it, emit) }
             // The whitespace of the last entry of the modifier list is actually placed outside the modifier list
             visitModifierChild(node, emit)
@@ -66,14 +66,14 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isWhiteSpace20) {
+        if (node.isWhiteSpace) {
             return
         }
         node
-            .nextSibling { it.isWhiteSpace20 && it.nextLeaf?.isPartOfComment20 != true }
+            .nextSibling { it.isWhiteSpace && it.nextLeaf?.isPartOfComment != true }
             ?.takeUnless {
                 // A single newline after a comment is always ok and does not need further checking.
-                it.text.trim(' ', '\t').contains('\n') && it.prevLeaf?.isPartOfComment20 == true
+                it.text.trim(' ', '\t').contains('\n') && it.prevLeaf?.isPartOfComment == true
             }?.let { whitespace ->
                 when {
                     node.isAnnotation() -> {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRule.kt
index 12bc556..aef410e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRule.kt
@@ -19,13 +19,13 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -101,7 +101,7 @@
             return
         }
 
-        if (!node.prevSibling20!!.textContains('\n')) {
+        if (!node.prevSibling!!.textContains('\n')) {
             if (node.firstChildNode == null) {
                 // if block with an empty 'then' block
                 return
@@ -140,13 +140,13 @@
         val nextLeaves =
             node
                 .leaves(forward = true)
-                .takeWhile { it.isWhiteSpaceWithoutNewline20 || it.isPartOfComment20 }
+                .takeWhile { it.isWhiteSpaceWithoutNewline || it.isPartOfComment }
                 .toList()
-                .dropLastWhile { it.isWhiteSpaceWithoutNewline20 }
+                .dropLastWhile { it.isWhiteSpaceWithoutNewline }
 
         prevLeaves
             .firstOrNull()
-            .takeIf { it.isWhiteSpace20 }
+            .takeIf { it.isWhiteSpace }
             ?.replaceTextWith(" ")
         KtBlockExpression(null).apply {
             val previousChild = node.firstChildNode
@@ -154,18 +154,18 @@
             addChild(LeafPsiElement(LBRACE, "{"))
             addChild(PsiWhiteSpaceImpl(indentConfig.childIndentOf(node)))
             prevLeaves
-                .dropWhile { it.isWhiteSpace20 }
+                .dropWhile { it.isWhiteSpace }
                 .forEach(::addChild)
             addChild(previousChild)
             nextLeaves.forEach(::addChild)
-            addChild(PsiWhiteSpaceImpl(node.indent20))
+            addChild(PsiWhiteSpaceImpl(node.indent))
             addChild(LeafPsiElement(RBRACE, "}"))
         }
 
         // Make sure else starts on same line as newly inserted right brace
         if (node.elementType == THEN) {
             node
-                .nextSibling { !it.isPartOfComment20 }
+                .nextSibling { !it.isPartOfComment }
                 ?.upsertWhitespaceBeforeMe(" ")
         }
     }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineExpressionWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineExpressionWrappingRule.kt
index b4890c9..478919a 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineExpressionWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineExpressionWrappingRule.kt
@@ -40,17 +40,17 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesForwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -113,17 +113,17 @@
     ) {
         if (node.containsWhitespaceWithNewline() && node.needToWrapMultilineExpression()) {
             node
-                .prevLeaf { !it.isPartOfComment20 }
-                .takeUnless { it.isWhiteSpaceWithNewline20 }
+                .prevLeaf { !it.isPartOfComment }
+                .takeUnless { it.isWhiteSpaceWithNewline }
                 ?.let { prevLeaf ->
                     emit(node.startOffset, "A multiline expression should start on a new line", true)
                         .ifAutocorrectAllowed {
                             node.upsertWhitespaceBeforeMe(indentConfig.siblingIndentOf(node))
                             val leafOnSameLineAfterMultilineExpression =
                                 node
-                                    .lastChildLeafOrSelf20
-                                    .nextLeaf { !it.isWhiteSpaceWithoutNewline20 && !it.isPartOfComment20 }
-                                    ?.takeIf { !it.isWhiteSpaceWithNewline20 }
+                                    .lastChildLeafOrSelf
+                                    .nextLeaf { !it.isWhiteSpaceWithoutNewline && !it.isPartOfComment }
+                                    ?.takeIf { !it.isWhiteSpaceWithNewline }
                             when {
                                 leafOnSameLineAfterMultilineExpression == null -> {
                                     Unit
@@ -161,11 +161,11 @@
     }
 
     private fun ASTNode.containsWhitespaceWithNewline(): Boolean {
-        val lastLeaf = lastChildLeafOrSelf20
-        return firstChildLeafOrSelf20
+        val lastLeaf = lastChildLeafOrSelf
+        return firstChildLeafOrSelf
             .leavesForwardsIncludingSelf
             .takeWhile { it != lastLeaf }
-            .any { it.isWhiteSpaceWithNewline20 || it.isRegularStringPartWithNewline() }
+            .any { it.isWhiteSpaceWithNewline || it.isRegularStringPartWithNewline() }
     }
 
     private fun ASTNode.isRegularStringPartWithNewline() =
@@ -180,7 +180,7 @@
 
     private fun ASTNode.isValueInAnAssignment() =
         null !=
-            prevCodeSibling20
+            prevCodeSibling
                 ?.takeIf { it.elementType == EQ || it.elementType == OPERATION_REFERENCE }
                 ?.takeUnless { functionBodyExpressionWrapping == default && it.parent?.elementType == FUN }
                 ?.takeUnless { it.isElvisOperator() }
@@ -188,7 +188,7 @@
                     it
                         .closingParenthesisOfFunctionOrNull()
                         ?.prevLeaf
-                        .isWhiteSpaceWithNewline20
+                        .isWhiteSpaceWithNewline
                 }
 
     private fun ASTNode?.isElvisOperator() =
@@ -220,7 +220,7 @@
     private fun ASTNode.isRightHandSideOfBinaryExpression() =
         null !=
             takeIf { it.parent?.elementType == BINARY_EXPRESSION }
-                .takeIf { it?.prevCodeSibling20?.elementType == OPERATION_REFERENCE }
+                .takeIf { it?.prevCodeSibling?.elementType == OPERATION_REFERENCE }
 
     private companion object {
         // Based  on https://kotlinlang.org/spec/expressions.html#expressions
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineLoopRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineLoopRule.kt
index c4b5cb8..7d5fe3c 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineLoopRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultilineLoopRule.kt
@@ -16,10 +16,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
@@ -89,13 +89,13 @@
         val nextLeaves =
             node
                 .leaves(forward = true)
-                .takeWhile { it.isWhiteSpaceWithoutNewline20 || it.isPartOfComment20 }
+                .takeWhile { it.isWhiteSpaceWithoutNewline || it.isPartOfComment }
                 .toList()
-                .dropLastWhile { it.isWhiteSpaceWithoutNewline20 }
+                .dropLastWhile { it.isWhiteSpaceWithoutNewline }
 
         prevLeaves
             .firstOrNull()
-            .takeIf { it.isWhiteSpace20 }
+            .takeIf { it.isWhiteSpace }
             ?.replaceTextWith(" ")
         KtBlockExpression(null).apply {
             val previousChild = node.firstChildNode
@@ -103,16 +103,16 @@
             addChild(LeafPsiElement(LBRACE, "{"))
             addChild(PsiWhiteSpaceImpl(indentConfig.childIndentOf(node)))
             prevLeaves
-                .dropWhile { it.isWhiteSpace20 }
+                .dropWhile { it.isWhiteSpace }
                 .forEach(::addChild)
             addChild(previousChild)
             nextLeaves.forEach(::addChild)
-            addChild(PsiWhiteSpaceImpl(node.indent20))
+            addChild(PsiWhiteSpaceImpl(node.indent))
             addChild(LeafPsiElement(RBRACE, "}"))
         }
 
         node
-            .nextSibling { !it.isPartOfComment20 }
+            .nextSibling { !it.isPartOfComment }
             ?.upsertWhitespaceBeforeMe(" ")
     }
 }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineBeforeRbraceRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineBeforeRbraceRule.kt
index 20f654e..d3cf613 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineBeforeRbraceRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineBeforeRbraceRule.kt
@@ -6,7 +6,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -18,7 +18,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isWhiteSpaceWithNewline20 &&
+        if (node.isWhiteSpaceWithNewline &&
             node.nextLeaf?.elementType == RBRACE
         ) {
             val split = node.getText().split("\n")
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineInListRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineInListRule.kt
index b2cf452..0e5996d 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineInListRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLineInListRule.kt
@@ -14,10 +14,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -32,7 +32,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (!node.isWhiteSpace20) {
+        if (!node.isWhiteSpace) {
             return
         }
 
@@ -50,7 +50,7 @@
         // the SUPER_TYPE_LIST of a CLASS the whitespaces before the first super type is a child of the CLASS. The whitespace after the last
         // SUPER_TYPE is part of the class only when the class has a body.
         node
-            .nextSibling20
+            .nextSibling
             ?.elementType
             ?.takeIf { it in LIST_TYPES }
             ?.let { treeParentElementType ->
@@ -68,7 +68,7 @@
         // the SUPER_TYPE_LIST of a CLASS the whitespaces before the first super type is a child of the CLASS. The whitespace after the last
         // SUPER_TYPE is part of the class only when the class has a body.
         node
-            .prevSibling20
+            .prevSibling
             ?.elementType
             ?.takeIf { it in LIST_TYPES }
             ?.let { treeParentElementType ->
@@ -76,7 +76,7 @@
                     node = node,
                     emit = emit,
                     partOfElementType = treeParentElementType,
-                    replaceWithSingeSpace = node.nextSibling20?.elementType == CLASS_BODY,
+                    replaceWithSingeSpace = node.nextSibling?.elementType == CLASS_BODY,
                 )
             }
     }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLinesInChainedMethodCallsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLinesInChainedMethodCallsRule.kt
index 610d39e..6f5a6ec 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLinesInChainedMethodCallsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoBlankLinesInChainedMethodCallsRule.kt
@@ -5,7 +5,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -17,7 +17,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        val isBlankLine = node.isWhiteSpace20 && node.text.contains("\n\n")
+        val isBlankLine = node.isWhiteSpace && node.text.contains("\n\n")
         if (isBlankLine && node.parent?.elementType == DOT_QUALIFIED_EXPRESSION) {
             emit(node.startOffset + 1, "Needless blank line(s)", true)
                 .ifAutocorrectAllowed {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveBlankLinesRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveBlankLinesRule.kt
index bcfc1ec..d907769 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveBlankLinesRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveBlankLinesRule.kt
@@ -8,12 +8,12 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -24,7 +24,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isWhiteSpace20 && node.prevSibling20 != null) {
+        if (node.isWhiteSpace && node.prevSibling != null) {
             val text = node.getText()
             val newLineCount = text.count { it == '\n' }
             if (newLineCount < 2) {
@@ -67,7 +67,7 @@
             ?.let { prevNode ->
                 prevNode.elementType == IDENTIFIER &&
                     prevNode.parent?.elementType == CLASS &&
-                    this.nextSibling20?.elementType == PRIMARY_CONSTRUCTOR
+                    this.nextSibling?.elementType == PRIMARY_CONSTRUCTOR
             }
             ?: false
 }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveCommentsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveCommentsRule.kt
index 569b8c5..009c4ff 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveCommentsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoConsecutiveCommentsRule.kt
@@ -10,7 +10,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -34,7 +34,7 @@
     ) {
         node
             .takeIf { it.isStartOfComment() }
-            ?.prevLeaf { !it.isWhiteSpace20 }
+            ?.prevLeaf { !it.isWhiteSpace }
             ?.takeIf { previousNonWhiteSpace -> previousNonWhiteSpace.isEndOfComment() }
             ?.let { previousComment ->
                 when {
@@ -103,7 +103,7 @@
                     previousComment.elementType != node.elementType &&
                         node
                             .prevLeaf
-                            .takeIf { it.isWhiteSpace20 }
+                            .takeIf { it.isWhiteSpace }
                             ?.text
                             .orEmpty()
                             .count { it == '\n' } > 1 -> {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyClassBodyRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyClassBodyRule.kt
index eb99735..dfa7021 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyClassBodyRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyClassBodyRule.kt
@@ -8,13 +8,13 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -33,7 +33,7 @@
             emit(node.startOffset, "Unnecessary block (\"{}\")", true)
                 .ifAutocorrectAllowed {
                     // remove space between declaration and block
-                    node.prevSibling20.takeIf { it.isWhiteSpace20 }?.remove()
+                    node.prevSibling.takeIf { it.isWhiteSpace }?.remove()
                     // remove block
                     node.remove()
                 }
@@ -43,13 +43,13 @@
     private fun ASTNode.isEmptyBlockBody(): Boolean =
         firstChildNode != null &&
             firstChildNode.elementType == LBRACE &&
-            firstChildNode.nextLeaf { !it.isWhiteSpace20 }?.elementType == RBRACE
+            firstChildNode.nextLeaf { !it.isWhiteSpace }?.elementType == RBRACE
 
     private fun isNotCompanion(node: ASTNode): Boolean =
         node
             .parent
             ?.firstChildNode
-            ?.children20
+            ?.children
             .orEmpty()
             .none { it.text == "companion" }
 }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFileRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFileRule.kt
index e978fd0..ccf76be 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFileRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFileRule.kt
@@ -8,9 +8,9 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isRoot20
+import com.pinterest.ktlint.rule.engine.core.api.isRoot
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 
@@ -22,7 +22,7 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .takeIf { it.isRoot20 }
+            .takeIf { it.isRoot }
             ?.takeIf { it.isEmptyFile() }
             ?.let { emit(0, "File '${node.getFileName()}' should not be empty", false) }
     }
@@ -37,7 +37,7 @@
 
     private fun ASTNode.isEmptyFile(): Boolean =
         null ==
-            children20
+            children
                 .firstOrNull {
                     it.isCode &&
                         it.elementType != PACKAGE_DIRECTIVE &&
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInClassBodyRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInClassBodyRule.kt
index fa9577b..e3c5b18 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInClassBodyRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInClassBodyRule.kt
@@ -12,7 +12,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -48,7 +48,7 @@
             node
                 .firstChildNode // LBRACE
                 .nextLeaf
-                .takeIf { it.isWhiteSpaceWithNewline20 }
+                .takeIf { it.isWhiteSpaceWithNewline }
                 ?.let { whitespace ->
                     val countNewlines =
                         whitespace
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInMethodBlockRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInMethodBlockRule.kt
index af596c6..e302a56 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInMethodBlockRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoEmptyFirstLineInMethodBlockRule.kt
@@ -10,7 +10,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
@@ -24,7 +24,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isWhiteSpaceWithNewline20 &&
+        if (node.isWhiteSpaceWithNewline &&
             node.prevLeaf?.elementType == LBRACE &&
             node.isPartOf(FUN) &&
             // Allow:
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakAfterElseRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakAfterElseRule.kt
index 1a55cc6..25d83b9 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakAfterElseRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakAfterElseRule.kt
@@ -8,7 +8,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
@@ -21,7 +21,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isWhiteSpaceWithNewline20 &&
+        if (node.isWhiteSpaceWithNewline &&
             node.prevLeaf?.elementType == ELSE_KEYWORD &&
             node.nextLeaf?.elementType.let { it == IF_KEYWORD || it == LBRACE }
         ) {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakBeforeAssignmentRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakBeforeAssignmentRule.kt
index 0cdb443..2706e8f 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakBeforeAssignmentRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoLineBreakBeforeAssignmentRule.kt
@@ -7,11 +7,11 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -35,8 +35,8 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         assignmentNode
-            .prevSibling20
-            .takeIf { it.isWhiteSpaceWithNewline20 }
+            .prevSibling
+            .takeIf { it.isWhiteSpaceWithNewline }
             ?.let { unexpectedNewlineBeforeAssignment ->
                 emit(unexpectedNewlineBeforeAssignment.startOffset, "Line break before assignment is not allowed", true)
                     .ifAutocorrectAllowed {
@@ -47,18 +47,18 @@
                             .takeWhile { !it.isCode }
                             .last()
                             .let { before ->
-                                if (!before.prevSibling20.isWhiteSpace20) {
+                                if (!before.prevSibling.isWhiteSpace) {
                                     parent.addChild(PsiWhiteSpaceImpl(" "), before)
                                 }
                                 parent.addChild(LeafPsiElement(EQ, "="), before)
-                                if (!before.isWhiteSpace20) {
+                                if (!before.isWhiteSpace) {
                                     parent.addChild(PsiWhiteSpaceImpl(" "), before)
                                 }
                             }
                         // Cleanup old assignment and whitespace after it. The indent before the old assignment is kept unchanged
                         assignmentNode
-                            .nextSibling20
-                            .takeIf { it.isWhiteSpace20 }
+                            .nextSibling
+                            .takeIf { it.isWhiteSpace }
                             ?.remove()
                         assignmentNode.remove()
                     }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoMultipleSpacesRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoMultipleSpacesRule.kt
index bb5fdbe..142c38e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoMultipleSpacesRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoMultipleSpacesRule.kt
@@ -7,9 +7,9 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -21,7 +21,7 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .takeIf { node.isWhiteSpace20 }
+            .takeIf { node.isWhiteSpace }
             .takeUnless { node.isPossibleAlignmentOfKdocTag() }
             ?.let {
                 val beforeIndentation = node.removeIndentation()
@@ -40,7 +40,7 @@
     // allow multiple spaces in KDoc in case of KDOC_TAG for alignment, e.g.
     // @param foo      stuff
     // @param foobar   stuff2
-    private fun ASTNode.isPossibleAlignmentOfKdocTag() = prevSibling20?.elementType == KDOC_MARKDOWN_LINK && parent?.elementType == KDOC_TAG
+    private fun ASTNode.isPossibleAlignmentOfKdocTag() = prevSibling?.elementType == KDOC_MARKDOWN_LINK && parent?.elementType == KDOC_TAG
 }
 
 public val NO_MULTIPLE_SPACES_RULE_ID: RuleId = NoMultipleSpacesRule().ruleId
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSemicolonsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSemicolonsRule.kt
index b9fb8a9..4ab73bb 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSemicolonsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSemicolonsRule.kt
@@ -21,10 +21,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.hasModifier
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
@@ -53,14 +53,14 @@
                 .ifAutocorrectAllowed {
                     val prevLeaf = node.prevLeaf
                     node.remove()
-                    if ((prevLeaf != null && prevLeaf.isWhiteSpace20) &&
-                        (nextLeaf == null || nextLeaf.isWhiteSpace20)
+                    if ((prevLeaf != null && prevLeaf.isWhiteSpace) &&
+                        (nextLeaf == null || nextLeaf.isWhiteSpace)
                     ) {
                         prevLeaf.remove()
                     }
                 }
-        } else if (!nextLeaf.isWhiteSpace20) {
-            if (node.prevLeaf.isWhiteSpaceWithNewline20) {
+        } else if (!nextLeaf.isWhiteSpace) {
+            if (node.prevLeaf.isWhiteSpaceWithNewline) {
                 return
             }
             // todo: move to a separate rule
@@ -77,7 +77,7 @@
                 true
             }
 
-            this.isWhiteSpace20 -> {
+            this.isWhiteSpace -> {
                 nextLeaf {
                     it.isCode &&
                         it.findParentByType(KDOC) == null &&
@@ -135,14 +135,14 @@
     private fun ASTNode?.getLastCodeLeafBeforeClosingOfClassBody() =
         this
             ?.findParentByType(CLASS_BODY)
-            ?.lastChildLeafOrSelf20
+            ?.lastChildLeafOrSelf
             ?.prevCodeLeaf
 
     private fun ASTNode?.isEnumClassWithoutValues() =
         this
             ?.takeIf { !it.isLastCodeLeafBeforeClosingOfClassBody() }
             ?.findParentByType(CLASS_BODY)
-            ?.takeIf { this == it.firstChildNode.nextCodeSibling20 }
+            ?.takeIf { this == it.firstChildNode.nextCodeSibling }
             ?.findParentByType(CLASS)
             ?.hasModifier(ENUM_KEYWORD)
             ?: false
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSingleLineBlockCommentRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSingleLineBlockCommentRule.kt
index 3cdb308..60b1547 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSingleLineBlockCommentRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoSingleLineBlockCommentRule.kt
@@ -10,11 +10,11 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
@@ -47,9 +47,9 @@
             val afterBlockComment =
                 node
                     .leaves()
-                    .takeWhile { it.isWhiteSpaceWithoutNewline20 }
+                    .takeWhile { it.isWhiteSpaceWithoutNewline }
                     .firstOrNull()
-                    ?: node.lastChildLeafOrSelf20
+                    ?: node.lastChildLeafOrSelf
 
             if (!node.textContains('\n') &&
                 afterBlockComment.nextLeaf.isWhitespaceWithNewlineOrNull()
@@ -59,9 +59,9 @@
                         val beforeBlockComment =
                             node
                                 .leaves(false)
-                                .takeWhile { it.isWhiteSpaceWithoutNewline20 }
+                                .takeWhile { it.isWhiteSpaceWithoutNewline }
                                 .firstOrNull()
-                                ?: node.firstChildLeafOrSelf20
+                                ?: node.firstChildLeafOrSelf
                         beforeBlockComment
                             .prevLeaf
                             .takeIf { !it.isWhitespaceWithNewlineOrNull() }
@@ -81,7 +81,7 @@
         rawRemove()
     }
 
-    private fun ASTNode?.isWhitespaceWithNewlineOrNull() = this == null || this.isWhiteSpaceWithNewline20
+    private fun ASTNode?.isWhitespaceWithNewlineOrNull() = this == null || this.isWhiteSpaceWithNewline
 }
 
 public val NO_SINGLE_LINE_BLOCK_COMMENT_RULE_ID: RuleId = NoSingleLineBlockCommentRule().ruleId
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoTrailingSpacesRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoTrailingSpacesRule.kt
index d8fad2b..06efb67 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoTrailingSpacesRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoTrailingSpacesRule.kt
@@ -1,22 +1,19 @@
 package com.pinterest.ktlint.ruleset.standard.rules
 
 import com.pinterest.ktlint.rule.engine.core.api.AutocorrectDecision
-import com.pinterest.ktlint.rule.engine.core.api.ElementType
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.EOL_COMMENT
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.KDOC
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.KDOC_END
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.KDOC_LEADING_ASTERISK
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.KDOC_TEXT
-import com.pinterest.ktlint.rule.engine.core.api.ElementType.WHITE_SPACE
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -28,7 +25,7 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         if (node.isPartOfKDoc()) {
-            if (node.isWhiteSpace20 && node.hasTrailingSpacesBeforeNewline()) {
+            if (node.isWhiteSpace && node.hasTrailingSpacesBeforeNewline()) {
                 val offsetOfSpaceBeforeNewlineInText = node.text.indexOf(" \n")
                 val offsetOfFirstSpaceBeforeNewlineInText =
                     node
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnitReturnRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnitReturnRule.kt
index 46b43be..0f3aa58 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnitReturnRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnitReturnRule.kt
@@ -9,8 +9,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -27,7 +27,7 @@
         if (node.elementType == TYPE_REFERENCE &&
             node.text == "Unit" &&
             node.parent?.elementType == FUN &&
-            node.nextCodeSibling20?.firstChildNode?.elementType == LBRACE
+            node.nextCodeSibling?.firstChildNode?.elementType == LBRACE
         ) {
             emit(node.startOffset, "Unnecessary \"Unit\" return type", true)
                 .ifAutocorrectAllowed {
@@ -38,14 +38,14 @@
                             // Remove space after colon when not followed by Unit node
                             node
                                 .nextLeaf
-                                .takeIf { it.isWhiteSpace20 }
+                                .takeIf { it.isWhiteSpace }
                                 ?.takeIf { it.nextLeaf != node }
                                 ?.remove()
                             colonNode.remove()
                         }
                     node
                         .prevLeaf
-                        .takeIf { it.isWhiteSpace20 }
+                        .takeIf { it.isWhiteSpace }
                         ?.takeIf { it.prevLeaf?.elementType != COLON }
                         ?.remove()
                     node.remove()
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnusedImportsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnusedImportsRule.kt
index 4f83089..6bc17e4 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnusedImportsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NoUnusedImportsRule.kt
@@ -17,14 +17,14 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isRoot20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isRoot
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -59,7 +59,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isRoot20) {
+        if (node.isRoot) {
             rootNode = node
         }
         when (node.elementType) {
@@ -169,13 +169,13 @@
                 ) {
                     emit(node.startOffset, "Unused import", true)
                         .ifAutocorrectAllowed {
-                            val nextSibling = node.nextSibling20
+                            val nextSibling = node.nextSibling
                             if (nextSibling == null) {
                                 // Last import
                                 node
-                                    .lastChildLeafOrSelf20
+                                    .lastChildLeafOrSelf
                                     .nextLeaf
-                                    ?.takeIf { it.isWhiteSpaceWithNewline20 }
+                                    ?.takeIf { it.isWhiteSpaceWithNewline }
                                     ?.let { whitespace ->
                                         if (node.prevLeaf == null) {
                                             // Also it was the first import, and it is not preceded by any other node containing some text. So
@@ -193,7 +193,7 @@
                                     }
                             } else {
                                 nextSibling
-                                    .takeIf { it.isWhiteSpaceWithNewline20 }
+                                    .takeIf { it.isWhiteSpaceWithNewline }
                                     ?.remove()
                             }
                             importDirective.delete()
@@ -215,20 +215,20 @@
         require(this.elementType == IMPORT_DIRECTIVE)
         when {
             parent?.firstChildNode == this -> {
-                nextSibling20
-                    ?.takeIf { it.isWhiteSpaceWithNewline20 }
+                nextSibling
+                    ?.takeIf { it.isWhiteSpaceWithNewline }
                     ?.remove()
             }
 
             parent?.lastChildNode == this -> {
-                prevSibling20
-                    ?.takeIf { it.isWhiteSpaceWithNewline20 }
+                prevSibling
+                    ?.takeIf { it.isWhiteSpaceWithNewline }
                     ?.remove()
             }
 
             else -> {
                 nextLeaf
-                    ?.takeIf { it.isWhiteSpaceWithNewline20 }
+                    ?.takeIf { it.isWhiteSpaceWithNewline }
                     ?.remove()
             }
         }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NullableTypeSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NullableTypeSpacingRule.kt
index 7aa918b..f6d861e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NullableTypeSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/NullableTypeSpacingRule.kt
@@ -7,7 +7,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -23,7 +23,7 @@
         node
             .takeIf { node.elementType == QUEST }
             ?.prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.let { whiteSpaceBeforeQuest ->
                 emit(whiteSpaceBeforeQuest.startOffset, "Unexpected whitespace", true)
                     .ifAutocorrectAllowed {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PackageNameRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PackageNameRule.kt
index 7a0a36a..e4aa65f 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PackageNameRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PackageNameRule.kt
@@ -7,7 +7,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import com.pinterest.ktlint.ruleset.standard.rules.internal.regExIgnoringDiacriticsAndStrokesOnLetters
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -24,7 +24,7 @@
         node
             .takeIf { node.elementType == PACKAGE_DIRECTIVE }
             ?.firstChildNode
-            ?.nextCodeSibling20
+            ?.nextCodeSibling
             ?.takeIf { it.elementType == DOT_QUALIFIED_EXPRESSION || it.elementType == REFERENCE_EXPRESSION }
             ?.let { expression ->
                 if (expression.text.contains('_')) {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListSpacingRule.kt
index bf7c132..0d09d81 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListSpacingRule.kt
@@ -14,21 +14,21 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.dropTrailingEolComment
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.lineLength
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
@@ -71,12 +71,12 @@
         require(node.elementType == VALUE_PARAMETER_LIST)
         val countValueParameters =
             node
-                .children20
+                .children
                 .count { it.elementType == VALUE_PARAMETER }
         var valueParameterCount = 0
         val iterator =
             node
-                .children20
+                .children
                 // Store elements in list before changing them as otherwise only one element is being changed
                 .toList()
                 .iterator()
@@ -102,11 +102,11 @@
                             // Avoid conflict with comment spacing rule which requires a whitespace before the
                             // EOL-comment
                         }
-                    } else if (el.nextCodeSibling20?.elementType == COMMA) {
+                    } else if (el.nextCodeSibling?.elementType == COMMA) {
                         // No whitespace between parameter name and comma allowed
                         removeUnexpectedWhiteSpace(el, emit)
-                    } else if (el.isWhiteSpace20 && el.isNotIndent() && el.isNotSingleSpace()) {
-                        require(el.prevCodeSibling20?.elementType == COMMA)
+                    } else if (el.isWhiteSpace && el.isNotIndent() && el.isNotSingleSpace()) {
+                        require(el.prevCodeSibling?.elementType == COMMA)
                         replaceWithSingleSpace(el, emit)
                     }
                 }
@@ -115,7 +115,7 @@
                     // Comma, except when it is the trailing comma, must be followed by whitespace
                     el
                         .nextLeaf
-                        ?.takeUnless { it.isWhiteSpace20 || it.elementType == RPAR }
+                        ?.takeUnless { it.isWhiteSpace || it.elementType == RPAR }
                         ?.let { addMissingWhiteSpaceAfterMe(el, emit) }
                 }
 
@@ -127,7 +127,7 @@
         }
     }
 
-    private fun ASTNode.containsNoComments() = children20.none { it.isPartOfComment20 }
+    private fun ASTNode.containsNoComments() = children.none { it.isPartOfComment }
 
     private fun visitValueParameter(
         node: ASTNode,
@@ -153,8 +153,8 @@
     ) {
         require(node.elementType == MODIFIER_LIST)
         node
-            .children20
-            .filter { it.isWhiteSpace20 }
+            .children
+            .filter { it.isWhiteSpace }
             // Store elements in the list before changing them as otherwise only the first whitespace is being changed
             .toList()
             .forEach { visitWhiteSpaceAfterModifier(it, emit) }
@@ -178,8 +178,8 @@
     ) {
         require(node.elementType == MODIFIER_LIST)
         node
-            .nextSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            .nextSibling
+            ?.takeIf { it.isWhiteSpace }
             ?.let { visitWhiteSpaceAfterModifier(it, emit) }
     }
 
@@ -190,7 +190,7 @@
         node
             .findChildByType(COLON)
             ?.prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.let { whiteSpaceBeforeColon ->
                 removeUnexpectedWhiteSpace(whiteSpaceBeforeColon, emit)
             }
@@ -203,7 +203,7 @@
         val colonNode = node.findChildByType(COLON) ?: return
         colonNode
             .nextLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             .let { whiteSpaceAfterColon ->
                 if (whiteSpaceAfterColon == null) {
                     addMissingWhiteSpaceAfterMe(colonNode, emit)
@@ -243,10 +243,10 @@
 
     private fun ASTNode.isNotIndent(): Boolean = !isIndent()
 
-    private fun ASTNode.isIndent(): Boolean = isWhiteSpaceWithNewline20
+    private fun ASTNode.isIndent(): Boolean = isWhiteSpaceWithNewline
 
     private fun ASTNode.isNotSingleSpace(): Boolean {
-        require(isWhiteSpace20)
+        require(isWhiteSpace)
         return text != " "
     }
 
@@ -269,7 +269,7 @@
     }
 
     private fun ASTNode.getPrecedingModifier(): ASTNode? =
-        prevCodeSibling20
+        prevCodeSibling
             ?.let { prevCodeSibling ->
                 if (prevCodeSibling.elementType == MODIFIER_LIST) {
                     prevCodeSibling.lastChildNode
@@ -286,13 +286,13 @@
                 ?.findChildByType(MODIFIER_LIST)
 
     private fun ASTNode.hasTypeReferenceWhichDoesNotFitOnSameLineAsColon() =
-        takeIf { it.isWhiteSpaceWithNewline20 }
-            ?.nextCodeSibling20
+        takeIf { it.isWhiteSpaceWithNewline }
+            ?.nextCodeSibling
             ?.takeIf { it.elementType == TYPE_REFERENCE }
             ?.let { typeReference ->
                 val length =
                     // length of the previous line
-                    leavesOnLine20
+                    leavesOnLine
                         .dropTrailingEolComment()
                         .lineLength +
                         // single space before type reference
@@ -301,7 +301,7 @@
                         this.text.substringAfterLast("\n").length +
                         // length of line containing typeReference
                         typeReference
-                            .leavesOnLine20
+                            .leavesOnLine
                             .dropTrailingEolComment()
                             .lineLength
                 length > maxLineLength
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListWrappingRule.kt
index 27f518e..0cc32c3 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterListWrappingRule.kt
@@ -26,16 +26,16 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.leavesOnLine
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -98,12 +98,12 @@
             .takeUnless {
                 // skip when max line length is not exceeded
                 (node.column - 1 + node.textLength) <= maxLineLength
-            }?.takeUnless { it.isWhiteSpaceWithNewline20 }
+            }?.takeUnless { it.isWhiteSpaceWithNewline }
             ?.takeIf { it.isFunctionTypeWithNonEmptyValueParameterList() }
             ?.let { nullableType ->
                 nullableType
                     .findChildByType(LPAR)
-                    ?.takeUnless { it.nextLeaf?.isWhiteSpaceWithNewline20 == true }
+                    ?.takeUnless { it.nextLeaf?.isWhiteSpaceWithNewline == true }
                     ?.let { lpar ->
                         emit(
                             lpar.startOffset + 1,
@@ -115,7 +115,7 @@
                     }
                 nullableType
                     .findChildByType(RPAR)
-                    ?.takeUnless { it.prevLeaf?.isWhiteSpaceWithNewline20 == true }
+                    ?.takeUnless { it.prevLeaf?.isWhiteSpaceWithNewline == true }
                     ?.let { rpar ->
                         emit(
                             rpar.startOffset,
@@ -168,7 +168,7 @@
 
     private fun ASTNode.hasNoParameters(): Boolean {
         require(elementType == VALUE_PARAMETER_LIST)
-        return firstChildNode?.nextSibling20?.elementType == RPAR
+        return firstChildNode?.nextSibling?.elementType == RPAR
     }
 
     private fun ASTNode.isPartOfFunctionLiteralInNonKtlintOfficialCodeStyle(): Boolean {
@@ -178,7 +178,7 @@
 
     private fun ASTNode.isPartOfFunctionLiteralStartingOnSameLineAsClosingParenthesisOfPrecedingReferenceExpression(): Boolean {
         require(elementType == VALUE_PARAMETER_LIST)
-        return firstChildLeafOrSelf20
+        return firstChildLeafOrSelf
             .let { startOfFunctionLiteral ->
                 parent
                     ?.takeIf { it.elementType == FUNCTION_LITERAL }
@@ -187,7 +187,7 @@
                     ?.takeIf { it.parent?.parent?.elementType == CALL_EXPRESSION }
                     ?.leaves()
                     ?.takeWhile { it != startOfFunctionLiteral }
-                    ?.none { it.isWhiteSpaceWithNewline20 }
+                    ?.none { it.isWhiteSpaceWithNewline }
                     ?: false
             }
     }
@@ -221,9 +221,9 @@
 
     private fun isPrecededByComment(node: ASTNode) =
         node
-            .prevLeaf { !it.isWhiteSpace20 }
+            .prevLeaf { !it.isWhiteSpace }
             ?.prevLeaf
-            ?.isPartOfComment20
+            ?.isPartOfComment
             ?: false
 
     private fun intendedIndent(child: ASTNode): String =
@@ -269,7 +269,7 @@
                     .parent
                     ?.takeUnless { it.isValueParameterListInFunctionType() }
                     ?.prevLeaf
-                    ?.takeIf { it.isWhiteSpaceWithNewline20 }
+                    ?.takeIf { it.isWhiteSpaceWithNewline }
                     ?.let { whitespace ->
                         emit(child.startOffset, errorMessage(child), true)
                             .ifAutocorrectAllowed { whitespace.remove() }
@@ -286,13 +286,13 @@
                 val intendedIndent = intendedIndent(child)
                 val prevLeaf = child.prevLeaf
                 when {
-                    prevLeaf.isWhiteSpaceWithNewline20 -> {
+                    prevLeaf.isWhiteSpaceWithNewline -> {
                         // The current child is already wrapped to a new line. Checking and fixing the
                         // correct size of the indent is the responsibility of the IndentationRule.
                         return
                     }
 
-                    prevLeaf.isWhiteSpace20 -> {
+                    prevLeaf.isWhiteSpace -> {
                         // The current child needs to be wrapped to a newline.
                         emit(child.startOffset, errorMessage(child), true)
                             .ifAutocorrectAllowed {
@@ -325,9 +325,9 @@
 
     private fun ASTNode.isOnLineExceedingMaxLineLength(): Boolean =
         if (hasNoMaxLineLengthSuppression()) {
-            val stopLeaf = nextLeaf { it.isWhiteSpaceWithNewline20 }?.nextLeaf
+            val stopLeaf = nextLeaf { it.isWhiteSpaceWithNewline }?.nextLeaf
             val lineContent =
-                leavesOnLine20
+                leavesOnLine
                     .dropTrailingEolComment()
                     .takeWhile { it.prevLeaf != stopLeaf }
                     .joinToString(separator = "") { it.text }
@@ -351,7 +351,7 @@
             ?.takeIf { elementType == FUN }
             ?.findChildByType(TYPE_PARAMETER_LIST)
             ?.children()
-            ?.any { it.isWhiteSpaceWithNewline20 }
+            ?.any { it.isWhiteSpaceWithNewline }
             ?: false
 }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterWrappingRule.kt
index 29c4040..579a074 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ParameterWrappingRule.kt
@@ -19,13 +19,13 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesBackwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesForwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
@@ -90,12 +90,12 @@
         val baseIndentLength = node.indentWithoutNewlinePrefix.length
 
         // Find the first node after the indenting whitespace on the same line as the identifier
-        val nodeFirstChildLeafOrSelf = node.firstChildLeafOrSelf20
+        val nodeFirstChildLeafOrSelf = node.firstChildLeafOrSelf
         val fromNode =
             node
                 .findChildByType(IDENTIFIER)
                 ?.leavesBackwardsIncludingSelf
-                ?.firstOrNull { it.prevLeaf.isWhiteSpaceWithNewline20 || it == nodeFirstChildLeafOrSelf }
+                ?.firstOrNull { it.prevLeaf.isWhiteSpaceWithNewline || it == nodeFirstChildLeafOrSelf }
                 ?: node
 
         node
@@ -143,15 +143,15 @@
     }
 
     private fun ASTNode.orTrailingComma() =
-        lastChildLeafOrSelf20
+        lastChildLeafOrSelf
             .nextCodeLeaf
             ?.takeIf { it.elementType == COMMA }
             ?: this
 
     private fun ASTNode.sumOfTextLengthUntil(astNode: ASTNode): Int {
-        val stopAtLeaf = astNode.lastChildLeafOrSelf20
+        val stopAtLeaf = astNode.lastChildLeafOrSelf
         return leavesForwardsIncludingSelf
-            .takeWhile { !it.isWhiteSpaceWithNewline20 && it.prevLeaf != stopAtLeaf }
+            .takeWhile { !it.isWhiteSpaceWithNewline && it.prevLeaf != stopAtLeaf }
             .sumOf { it.textLength }
     }
 
@@ -168,7 +168,7 @@
                 "$line: ${if (autocorrectDecision == NO_AUTOCORRECT) "would have" else ""} inserted newline before ${node.text}"
             }
         }.ifAutocorrectAllowed {
-            node.upsertWhitespaceBeforeMe(node.indent20)
+            node.upsertWhitespaceBeforeMe(node.indent)
         }
     }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyNamingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyNamingRule.kt
index 07cf0a8..c6b170a 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyNamingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyNamingRule.kt
@@ -15,7 +15,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfigProperty
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.SafeEnumValueParser
@@ -121,7 +121,7 @@
 
     private fun ASTNode.isTopLevelValue() = parent?.elementType == FILE && containsValKeyword()
 
-    private fun ASTNode.containsValKeyword() = children20.any { it.elementType == VAL_KEYWORD }
+    private fun ASTNode.containsValKeyword() = children.any { it.elementType == VAL_KEYWORD }
 
     private fun ASTNode.isObjectValue() =
         parent?.elementType == CLASS_BODY &&
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyWrappingRule.kt
index 8a29166..126febb 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/PropertyWrappingRule.kt
@@ -17,12 +17,12 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.indentWithoutNewlinePrefix
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesBackwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesForwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -86,12 +86,12 @@
         val baseIndentLength = node.indentWithoutNewlinePrefix.length
 
         // Find the first node after the indenting whitespace on the same line as the identifier
-        val nodeFirstChildLeafOrSelf = node.firstChildLeafOrSelf20
+        val nodeFirstChildLeafOrSelf = node.firstChildLeafOrSelf
         val fromNode =
             node
                 .findChildByType(IDENTIFIER)
                 ?.leavesBackwardsIncludingSelf
-                ?.firstOrNull { it.prevLeaf.isWhiteSpaceWithNewline20 || it == nodeFirstChildLeafOrSelf }
+                ?.firstOrNull { it.prevLeaf.isWhiteSpaceWithNewline || it == nodeFirstChildLeafOrSelf }
                 ?: node
 
         node
@@ -139,9 +139,9 @@
     }
 
     private fun ASTNode.sumOfTextLengthUntil(astNode: ASTNode): Int {
-        val stopAtLeaf = astNode.lastChildLeafOrSelf20
+        val stopAtLeaf = astNode.lastChildLeafOrSelf
         return leavesForwardsIncludingSelf
-            .takeWhile { !it.isWhiteSpaceWithNewline20 && it.prevLeaf != stopAtLeaf }
+            .takeWhile { !it.isWhiteSpaceWithNewline && it.prevLeaf != stopAtLeaf }
             .sumOf { it.textLength }
     }
 
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundAngleBracketsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundAngleBracketsRule.kt
index 2e2575d..4411289 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundAngleBracketsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundAngleBracketsRule.kt
@@ -10,8 +10,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -34,7 +34,7 @@
             // Check for rogue spacing before an opening bracket, e.g. Map <String, Int>
             openingBracket
                 .prevLeaf
-                .takeIf { it.isWhiteSpace20 }
+                .takeIf { it.isWhiteSpace }
                 ?.let { beforeLeftAngle ->
                     // Ignore when the whitespace is preceded by certain keywords, e.g. fun <T> func(arg: T) {}
                     if (!ELEMENT_TYPES_ALLOWING_PRECEDING_WHITESPACE.contains(beforeLeftAngle.prevLeaf?.elementType)) {
@@ -46,9 +46,9 @@
             // Check for rogue spacing after an opening bracket
             openingBracket
                 .nextLeaf
-                .takeIf { it.isWhiteSpace20 }
+                .takeIf { it.isWhiteSpace }
                 ?.let { afterLeftAngle ->
-                    if (afterLeftAngle.isWhiteSpaceWithoutNewline20) {
+                    if (afterLeftAngle.isWhiteSpaceWithoutNewline) {
                         emit(afterLeftAngle.startOffset, "Unexpected spacing after \"<\"", true)
                             .ifAutocorrectAllowed {
                                 // when spacing does not include any new lines, e.g. Map< String, Int>
@@ -74,10 +74,10 @@
         val closingBracket = node.lastChildNode
         closingBracket
             ?.prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.let { beforeRightAngle ->
                 // Check for rogue spacing before a closing bracket
-                if (beforeRightAngle.isWhiteSpaceWithoutNewline20) {
+                if (beforeRightAngle.isWhiteSpaceWithoutNewline) {
                     emit(beforeRightAngle.startOffset, "Unexpected spacing before \">\"", true)
                         .ifAutocorrectAllowed {
                             // when spacing does not include any new lines, e.g. Map<String, Int >
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundColonRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundColonRule.kt
index d5e8571..12fcfe4 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundColonRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundColonRule.kt
@@ -18,15 +18,15 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
@@ -54,7 +54,7 @@
     ) {
         node
             .prevLeaf
-            ?.takeIf { it.isWhiteSpaceWithNewline20 }
+            ?.takeIf { it.isWhiteSpaceWithNewline }
             ?.let { prevLeaf ->
                 emit(prevLeaf.startOffset, "Unexpected newline before \":\"", true)
                     .ifAutocorrectAllowed {
@@ -70,12 +70,12 @@
                                 node
                                     .siblings(forward = true)
                                     .firstOrNull { it.elementType == EQ }
-                                    ?.nextSibling20
+                                    ?.nextSibling
                                     ?.let { nextSibling ->
                                         prevNonCodeElements.forEach {
                                             node.parent?.addChild(it, nextSibling)
                                         }
-                                        if (nextSibling.isWhiteSpace20) {
+                                        if (nextSibling.isWhiteSpace) {
                                             nextSibling.remove()
                                         }
                                         Unit
@@ -88,14 +88,14 @@
                                     val before =
                                         blockElement
                                             .firstChildNode
-                                            .nextSibling20
+                                            .nextSibling
                                     prevNonCodeElements
                                         .let {
-                                            if (it.first().isWhiteSpace20) {
+                                            if (it.first().isWhiteSpace) {
                                                 it.first().remove()
                                                 it.drop(1)
                                             }
-                                            if (it.last().isWhiteSpaceWithNewline20) {
+                                            if (it.last().isWhiteSpaceWithNewline) {
                                                 it.last().remove()
                                                 it.dropLast(1)
                                             } else {
@@ -107,12 +107,12 @@
                                 }
                             }
 
-                            prevLeaf.prevLeaf?.isPartOfComment20 == true -> {
+                            prevLeaf.prevLeaf?.isPartOfComment == true -> {
                                 val nextLeaf = node.nextLeaf
                                 prevNonCodeElements.forEach {
                                     node.parent?.addChild(it, nextLeaf)
                                 }
-                                if (nextLeaf != null && nextLeaf.isWhiteSpace20) {
+                                if (nextLeaf != null && nextLeaf.isWhiteSpace) {
                                     nextLeaf.remove()
                                 }
                             }
@@ -135,19 +135,19 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.prevSibling20.isWhiteSpaceWithoutNewline20 && node.noSpacingBefore) {
+        if (node.prevSibling.isWhiteSpaceWithoutNewline && node.noSpacingBefore) {
             emit(node.startOffset, "Unexpected spacing before \":\"", true)
                 .ifAutocorrectAllowed {
                     node
-                        .prevSibling20
+                        .prevSibling
                         ?.remove()
                 }
         }
-        if (node.nextSibling20.isWhiteSpaceWithoutNewline20 && node.spacingAfter) {
+        if (node.nextSibling.isWhiteSpaceWithoutNewline && node.spacingAfter) {
             emit(node.startOffset, "Unexpected spacing after \":\"", true)
                 .ifAutocorrectAllowed {
                     node
-                        .nextSibling20
+                        .nextSibling
                         ?.remove()
                 }
         }
@@ -157,8 +157,8 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        val missingSpacingBefore = !node.prevSibling20.isWhiteSpace20 && node.spacingBefore
-        val missingSpacingAfter = !node.nextSibling20.isWhiteSpace20 && node.noSpacingAfter
+        val missingSpacingBefore = !node.prevSibling.isWhiteSpace && node.spacingBefore
+        val missingSpacingAfter = !node.nextSibling.isWhiteSpace && node.noSpacingAfter
         when {
             missingSpacingBefore && missingSpacingAfter -> {
                 emit(node.startOffset, "Missing spacing around \":\"", true)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCommaRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCommaRule.kt
index 50d6274..dcb68f1 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCommaRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCommaRule.kt
@@ -8,12 +8,12 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfString20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfString
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -32,24 +32,24 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node is LeafPsiElement && node.textMatches(",") && !node.isPartOfString20) {
+        if (node is LeafPsiElement && node.textMatches(",") && !node.isPartOfString) {
             node
                 .prevLeaf
-                .takeIf { it.isWhiteSpace20 }
+                .takeIf { it.isWhiteSpace }
                 ?.let { prevLeaf ->
                     emit(prevLeaf.startOffset, "Unexpected spacing before \"${node.text}\"", true)
                         .ifAutocorrectAllowed {
                             val isPrecededByComment =
                                 prevLeaf
-                                    .prevLeaf { !it.isWhiteSpace20 }
-                                    ?.isPartOfComment20
+                                    .prevLeaf { !it.isWhiteSpace }
+                                    ?.isPartOfComment
                                     ?: false
-                            if (isPrecededByComment && prevLeaf.isWhiteSpaceWithNewline20) {
+                            if (isPrecededByComment && prevLeaf.isWhiteSpaceWithNewline) {
                                 // If comma is on new line and preceded by a comment, it should be moved before this comment
                                 // https://github.com/pinterest/ktlint/issues/367
                                 val previousStatement = node.prevCodeLeaf!!
-                                previousStatement.parent?.addChild(node.clone(), previousStatement.nextSibling20)
-                                node.nextLeaf.takeIf { it.isWhiteSpace20 }?.remove()
+                                previousStatement.parent?.addChild(node.clone(), previousStatement.nextSibling)
+                                node.nextLeaf.takeIf { it.isWhiteSpace }?.remove()
                                 node.remove()
                             } else {
                                 prevLeaf.remove()
@@ -58,7 +58,7 @@
                 }
             node
                 .nextLeaf
-                .takeUnless { it.isWhiteSpace20 }
+                .takeUnless { it.isWhiteSpace }
                 ?.takeUnless { it.elementType in rTokenSet }
                 ?.let {
                     emit(node.startOffset + 1, "Missing spacing after \"${node.text}\"", true)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCurlyRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCurlyRule.kt
index a8b9069..66f0cac 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCurlyRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundCurlyRule.kt
@@ -29,15 +29,15 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isLeaf20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfString20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isLeaf
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfString
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.leavesBackwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -77,7 +77,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isLeaf20 && !node.isPartOfString20) {
+        if (node.isLeaf && !node.isPartOfString) {
             val prevLeaf = node.prevLeaf
             val nextLeaf = node.nextLeaf
             val spacingBefore: Boolean
@@ -85,7 +85,7 @@
             when (node.elementType) {
                 LBRACE -> {
                     spacingBefore =
-                        prevLeaf.isWhiteSpace20 ||
+                        prevLeaf.isWhiteSpace ||
                         prevLeaf?.elementType == AT ||
                         (
                             (prevLeaf?.elementType == LPAR || prevLeaf?.elementType == LBRACKET) &&
@@ -94,8 +94,8 @@
                                         node.parent?.parent?.elementType == LAMBDA_EXPRESSION
                                 )
                         )
-                    spacingAfter = nextLeaf.isWhiteSpace20 || nextLeaf?.elementType == RBRACE
-                    if (prevLeaf.isWhiteSpaceWithoutNewline20 &&
+                    spacingAfter = nextLeaf.isWhiteSpace || nextLeaf?.elementType == RBRACE
+                    if (prevLeaf.isWhiteSpaceWithoutNewline &&
                         prevLeaf!!.isPrecededBy { it.elementType == LPAR || it.elementType == AT }
                     ) {
                         emit(node.startOffset, "Unexpected space before \"${node.text}\"", true)
@@ -118,7 +118,7 @@
                                                     node.parent?.addChildren(
                                                         leavesToMoveAfterCurly.first(),
                                                         leavesToMoveAfterCurly.last(),
-                                                        node.nextSibling20,
+                                                        node.nextSibling,
                                                     )
                                                 }
                                         }
@@ -129,10 +129,10 @@
                 }
 
                 RBRACE -> {
-                    spacingBefore = prevLeaf.isWhiteSpace20 || prevLeaf?.elementType == LBRACE
-                    spacingAfter = nextLeaf == null || nextLeaf.isWhiteSpace20 || shouldNotToBeSeparatedBySpace(nextLeaf)
+                    spacingBefore = prevLeaf.isWhiteSpace || prevLeaf?.elementType == LBRACE
+                    spacingAfter = nextLeaf == null || nextLeaf.isWhiteSpace || shouldNotToBeSeparatedBySpace(nextLeaf)
                     nextLeaf
-                        .takeIf { it.isWhiteSpaceWithoutNewline20 }
+                        .takeIf { it.isWhiteSpaceWithoutNewline }
                         ?.takeIf { shouldNotToBeSeparatedBySpace(it.nextLeaf) }
                         ?.let { leaf ->
                             emit(node.startOffset, "Unexpected space after \"${node.text}\"", true)
@@ -172,7 +172,7 @@
 
     private fun ASTNode.hasUnexpectedNewlineBeforeLbrace(): Boolean =
         also { require(it.elementType == LBRACE) }
-            .takeIf { prevLeaf.isWhiteSpaceWithNewline20 }
+            .takeIf { prevLeaf.isWhiteSpaceWithNewline }
             ?.let { parent?.elementType == CLASS_BODY || parent?.elementType == BLOCK }
             ?: false
 
@@ -183,7 +183,7 @@
 
     private fun ASTNode.isPrecededByEolComment() =
         prevLeaf
-            ?.isPartOfComment20
+            ?.isPartOfComment
             ?: false
 
     private fun shouldNotToBeSeparatedBySpace(leaf: ASTNode?): Boolean {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDotRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDotRule.kt
index 569be0d..ba76838 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDotRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDotRule.kt
@@ -6,8 +6,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -24,13 +24,13 @@
         if (node is LeafPsiElement && node.isCode && node.textMatches(".")) {
             node
                 .prevLeaf
-                .takeIf { it.isWhiteSpaceWithoutNewline20 }
+                .takeIf { it.isWhiteSpaceWithoutNewline }
                 ?.let { prevLeaf ->
                     emit(prevLeaf.startOffset, "Unexpected spacing before \"${node.text}\"", true)
                         .ifAutocorrectAllowed { prevLeaf.remove() }
                 }
             node.nextLeaf
-                .takeIf { it.isWhiteSpace20 }
+                .takeIf { it.isWhiteSpace }
                 ?.let { nextLeaf ->
                     emit(nextLeaf.startOffset, "Unexpected spacing after \"${node.text}\"", true)
                         .ifAutocorrectAllowed { nextLeaf.remove() }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDoubleColonRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDoubleColonRule.kt
index 36a54dc..4841404 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDoubleColonRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundDoubleColonRule.kt
@@ -9,11 +9,11 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -32,21 +32,21 @@
             var removeSingleWhiteSpace = false
             val spacingBefore =
                 when {
-                    node.isPartOf(CLASS_LITERAL_EXPRESSION) && prevLeaf.isWhiteSpace20 -> {
+                    node.isPartOf(CLASS_LITERAL_EXPRESSION) && prevLeaf.isWhiteSpace -> {
                         true
                     }
 
                     // Clazz::class
-                    node.isPartOf(CALLABLE_REFERENCE_EXPRESSION) && prevLeaf.isWhiteSpace20 -> {
+                    node.isPartOf(CALLABLE_REFERENCE_EXPRESSION) && prevLeaf.isWhiteSpace -> {
                         // String::length, ::isOdd
-                        if (node.prevSibling20 == null) { // compose(length, ::isOdd), val predicate = ::isOdd
+                        if (node.prevSibling == null) { // compose(length, ::isOdd), val predicate = ::isOdd
                             removeSingleWhiteSpace = true
                             prevLeaf
-                                .takeIf { it.isWhiteSpaceWithoutNewline20 }
+                                .takeIf { it.isWhiteSpaceWithoutNewline }
                                 ?.let { it.textLength > 1 }
                                 ?: false
                         } else { // String::length, List<String>::isEmpty
-                            prevLeaf.isWhiteSpaceWithoutNewline20
+                            prevLeaf.isWhiteSpaceWithoutNewline
                         }
                     }
 
@@ -54,7 +54,7 @@
                         false
                     }
                 }
-            val spacingAfter = nextLeaf.isWhiteSpace20
+            val spacingAfter = nextLeaf.isWhiteSpace
             when {
                 spacingBefore && spacingAfter -> {
                     emit(node.startOffset, "Unexpected spacing around \"${node.text}\"", true)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundKeywordRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundKeywordRule.kt
index 5392924..f7681ec 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundKeywordRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundKeywordRule.kt
@@ -22,8 +22,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -56,7 +56,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.elementType in tokenSet && node.parent?.elementType != KDOC_NAME && !node.nextLeaf.isWhiteSpace20) {
+        if (node.elementType in tokenSet && node.parent?.elementType != KDOC_NAME && !node.nextLeaf.isWhiteSpace) {
             emit(node.startOffset + node.text.length, "Missing spacing after \"${node.text}\"", true)
                 .ifAutocorrectAllowed { node.upsertWhitespaceAfterMe(" ") }
         }
@@ -64,7 +64,7 @@
             .takeIf { keywordsWithoutSpaces.contains(it.elementType) }
             .takeIf { node.isPropertyAccessorWithValueParameterList() }
             ?.nextLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.also { nextLeaf ->
                 emit(node.startOffset, "Unexpected spacing after \"${node.text}\"", true)
                     .ifAutocorrectAllowed { nextLeaf.remove() }
@@ -72,7 +72,7 @@
         if (noLFBeforeSet.contains(node.elementType)) {
             val prevLeaf = node.prevLeaf
             val isElseKeyword = node.elementType == ELSE_KEYWORD
-            if (prevLeaf.isWhiteSpaceWithNewline20 &&
+            if (prevLeaf.isWhiteSpaceWithNewline &&
                 (!isElseKeyword || node.parent?.elementType != WHEN_ENTRY)
             ) {
                 val rBrace = prevLeaf?.prevLeaf?.takeIf { it.elementType == RBRACE }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundOperatorsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundOperatorsRule.kt
index 86c1626..e5684d9 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundOperatorsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundOperatorsRule.kt
@@ -34,7 +34,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -81,8 +81,8 @@
         if (node.elementType in OPERATORS ||
             (node.elementType == IDENTIFIER && node.parent?.elementType == OPERATION_REFERENCE)
         ) {
-            val spacingBefore = node.prevLeaf.isWhiteSpace20
-            val spacingAfter = node.nextLeaf.isWhiteSpace20
+            val spacingBefore = node.prevLeaf.isWhiteSpace
+            val spacingAfter = node.nextLeaf.isWhiteSpace
             when {
                 !spacingBefore && !spacingAfter -> {
                     emit(node.startOffset, "Missing spacing around \"${node.text}\"", true)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundParensRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundParensRule.kt
index e17309c..8183648 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundParensRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundParensRule.kt
@@ -18,14 +18,14 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -56,11 +56,11 @@
 
     private fun ASTNode.isUnexpectedSpacingBeforeParenthesis(): Boolean =
         when {
-            prevLeaf.isWhiteSpaceWithNewline20 && hasNoNewlineAfterLpar() -> {
+            prevLeaf.isWhiteSpaceWithNewline && hasNoNewlineAfterLpar() -> {
                 true
             }
 
-            !prevLeaf.isWhiteSpaceWithoutNewline20 -> {
+            !prevLeaf.isWhiteSpaceWithoutNewline -> {
                 false
             }
 
@@ -78,7 +78,7 @@
                 // Disallow:
                 //    val foo = fn("foo" )
                 //    val foo = fn( )
-                prevLeaf?.prevSibling20?.elementType != LPAR
+                prevLeaf?.prevSibling?.elementType != LPAR
             }
 
             else -> {
@@ -88,7 +88,7 @@
 
     private fun ASTNode.isUnexpectedSpacingBetweenIdentifierAndElementList() =
         prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.takeIf {
                 // Disallow:
                 //     fun foo () {}
@@ -105,7 +105,7 @@
 
     private fun ASTNode.isUnexpectedSpacingInCallToSuper() =
         prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.let {
                 // Disallow:
                 //     class Foo : Bar {
@@ -117,7 +117,7 @@
 
     private fun ASTNode.isUnexpectedSpacingInExplicitConstructor() =
         prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.let {
                 // Disallow:
                 //     class Foo constructor ()
@@ -127,19 +127,19 @@
 
     private fun ASTNode.isUnexpectedSpacingInSuperTypeCallEntry() =
         prevLeaf
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.takeIf { it.isWhiteSpace }
             ?.let {
                 // Disallow:
                 //     class Foo : Bar ("test")
                 //     class Foo : Bar<String> ("test")
                 parent?.parent?.elementType == SUPER_TYPE_CALL_ENTRY &&
-                    it.prevSibling20?.elementType == CONSTRUCTOR_CALLEE
+                    it.prevSibling?.elementType == CONSTRUCTOR_CALLEE
             }
             ?: false
 
     private fun ASTNode.isUnexpectedSpacingAfterParenthesis(): Boolean =
         when {
-            elementType == LPAR && nextSibling20.isWhiteSpaceWithNewline20 && hasNoOtherNewlineBeforeRpar() -> {
+            elementType == LPAR && nextSibling.isWhiteSpaceWithNewline && hasNoOtherNewlineBeforeRpar() -> {
                 true
             }
 
@@ -160,28 +160,28 @@
         //     val foo = fn( )
         //     val foo = fn( "bar")
         //     val foo = ( (1 + 2) / 3)
-        isWhiteSpaceWithoutNewline20
+        isWhiteSpaceWithoutNewline
 
     private fun ASTNode.isUnexpectedNewlineAfterLpar() =
         // Disallow:
         //     val foo = fn(
         //         )
-        isWhiteSpaceWithNewline20 && nextLeaf?.elementType == RPAR
+        isWhiteSpaceWithNewline && nextLeaf?.elementType == RPAR
 
     private fun ASTNode.hasNoOtherNewlineBeforeRpar() =
-        nextSibling20
-            .takeIf { it.isWhiteSpaceWithNewline20 }
+        nextSibling
+            .takeIf { it.isWhiteSpaceWithNewline }
             ?.siblings()
             ?.takeWhile { it.elementType != RPAR }
-            ?.none { it.isWhiteSpaceWithNewline20 }
+            ?.none { it.isWhiteSpaceWithNewline }
             ?: false
 
     private fun ASTNode.isNextLeafAComment(): Boolean = nextLeaf?.elementType in commentTypes
 
     private fun ASTNode.hasNoNewlineAfterLpar() =
-        prevSibling20
-            .takeIf { it.isWhiteSpaceWithNewline20 }
-            ?.takeUnless { it.prevSibling20?.elementType == LPAR }
+        prevSibling
+            .takeIf { it.isWhiteSpaceWithNewline }
+            ?.takeUnless { it.prevSibling?.elementType == LPAR }
             ?.siblings(false)
             ?.takeWhile { it.elementType != LPAR }
             ?.none { it.textContains('\n') || it.elementType == EOL_COMMENT }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundRangeOperatorRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundRangeOperatorRule.kt
index 87b9e19..a5ab0f9 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundRangeOperatorRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundRangeOperatorRule.kt
@@ -7,7 +7,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.remove
@@ -25,7 +25,7 @@
             val prevLeaf = node.prevLeaf
             val nextLeaf = node.nextLeaf
             when {
-                prevLeaf.isWhiteSpace20 && nextLeaf.isWhiteSpace20 -> {
+                prevLeaf.isWhiteSpace && nextLeaf.isWhiteSpace -> {
                     emit(node.startOffset, "Unexpected spacing around \"${node.elementTypeDescription()}\"", true)
                         .ifAutocorrectAllowed {
                             prevLeaf?.remove()
@@ -33,12 +33,12 @@
                         }
                 }
 
-                prevLeaf != null && prevLeaf.isWhiteSpace20 -> {
+                prevLeaf != null && prevLeaf.isWhiteSpace -> {
                     emit(prevLeaf.startOffset, "Unexpected spacing before \"${node.elementTypeDescription()}\"", true)
                         .ifAutocorrectAllowed { prevLeaf.remove() }
                 }
 
-                nextLeaf != null && nextLeaf.isWhiteSpace20 -> {
+                nextLeaf != null && nextLeaf.isWhiteSpace -> {
                     emit(nextLeaf.startOffset, "Unexpected spacing after \"${node.elementTypeDescription()}\"", true)
                         .ifAutocorrectAllowed { nextLeaf.remove() }
                 }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundSquareBracketsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundSquareBracketsRule.kt
index a64cf26..1e4fc3e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundSquareBracketsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundSquareBracketsRule.kt
@@ -10,7 +10,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -53,11 +53,11 @@
                         //        ]
                         // Disallow:
                         //     @Foo(fooBar = ["foo", "bar" ])
-                        node.elementType == RBRACKET && prevLeaf.isWhiteSpaceWithoutNewline20
+                        node.elementType == RBRACKET && prevLeaf.isWhiteSpaceWithoutNewline
                     }
 
                     else -> {
-                        prevLeaf.isWhiteSpaceWithoutNewline20
+                        prevLeaf.isWhiteSpaceWithoutNewline
                     }
                 }
             val spacingAfter =
@@ -74,7 +74,7 @@
                 //        ]
                 // Disallow:
                 //     @Foo(fooBar = [ "foo", "bar"])
-                node.elementType == LBRACKET && nextLeaf.isWhiteSpaceWithoutNewline20
+                node.elementType == LBRACKET && nextLeaf.isWhiteSpaceWithoutNewline
             when {
                 spacingBefore && spacingAfter -> {
                     emit(node.startOffset, "Unexpected spacing around '${node.text}'", true)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundUnaryOperatorRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundUnaryOperatorRule.kt
index 743e8aa..14317aa 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundUnaryOperatorRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingAroundUnaryOperatorRule.kt
@@ -7,10 +7,10 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -28,15 +28,15 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         if (node.elementType == PREFIX_EXPRESSION || node.elementType == POSTFIX_EXPRESSION) {
-            val children = node.children20.toList()
+            val children = node.children.toList()
 
             // ignore: var a = + /* comment */ 1
-            if (children.any { it.isPartOfComment20 }) {
+            if (children.any { it.isPartOfComment }) {
                 return
             }
 
             children
-                .firstOrNull { it.isWhiteSpace20 }
+                .firstOrNull { it.isWhiteSpace }
                 ?.let { whiteSpace ->
                     emit(whiteSpace.startOffset, "Unexpected spacing in ${node.text.replace("\n", "\\n")}", true)
                         .ifAutocorrectAllowed { whiteSpace.remove() }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithAnnotationsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithAnnotationsRule.kt
index 7f8fa89..9d12697 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithAnnotationsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithAnnotationsRule.kt
@@ -8,15 +8,15 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isDeclaration20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isDeclaration
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -37,31 +37,31 @@
         }
     }
 
-    private fun ASTNode.isDeclarationOrPropertyAccessor() = isDeclaration20 || elementType == PROPERTY_ACCESSOR
+    private fun ASTNode.isDeclarationOrPropertyAccessor() = isDeclaration || elementType == PROPERTY_ACCESSOR
 
     private fun visitDeclaration(
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .prevCodeSibling20
+            .prevCodeSibling
             ?.takeIf { it.isDeclarationOrPropertyAccessor() }
             ?.takeIf { prevDeclaration -> hasNoBlankLineBetweenDeclarations(node, prevDeclaration) }
             ?.let {
-                val prevLeaf = node.prevCodeLeaf?.nextLeaf { it.isWhiteSpace20 }!!
+                val prevLeaf = node.prevCodeLeaf?.nextLeaf { it.isWhiteSpace }!!
                 emit(
                     prevLeaf.startOffset + 1,
                     "Declarations and declarations with annotations should have an empty space between.",
                     true,
                 ).ifAutocorrectAllowed {
-                    prevLeaf.upsertWhitespaceBeforeMe("\n".plus(node.indent20))
+                    prevLeaf.upsertWhitespaceBeforeMe("\n".plus(node.indent))
                 }
             }
     }
 
     private fun ASTNode.isAnnotated(): Boolean =
         findChildByType(MODIFIER_LIST)
-            ?.children20
+            ?.children
             ?.any { it.elementType == ANNOTATION_ENTRY }
             ?: false
 
@@ -74,7 +74,7 @@
         .takeWhile { it != prevDeclaration }
         .none { it.isBlankLine() }
 
-    private fun ASTNode.isBlankLine() = isWhiteSpace20 && text.count { it == '\n' } > 1
+    private fun ASTNode.isBlankLine() = isWhiteSpace && text.count { it == '\n' } > 1
 }
 
 public val SPACING_BETWEEN_DECLARATIONS_WITH_ANNOTATIONS_RULE_ID: RuleId = SpacingBetweenDeclarationsWithAnnotationsRule().ruleId
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithCommentsRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithCommentsRule.kt
index 436c927..4bbc22e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithCommentsRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenDeclarationsWithCommentsRule.kt
@@ -7,12 +7,12 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.TokenSets
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isDeclaration20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
+import com.pinterest.ktlint.rule.engine.core.api.isDeclaration
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -31,8 +31,8 @@
             .takeIf { it.elementType in TokenSets.COMMENTS }
             ?.takeUnless { it.isTailComment() }
             ?.parent
-            ?.takeIf { it.isDeclaration20 }
-            ?.takeIf { it.prevCodeSibling20.isDeclaration20 }
+            ?.takeIf { it.isDeclaration }
+            ?.takeIf { it.prevCodeSibling.isDeclaration }
             ?.let { visitCommentedDeclaration(it, emit) }
     }
 
@@ -43,7 +43,7 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .prevSibling20
+            .prevSibling
             ?.takeUnless { it.isBlankLine() }
             ?.let { prevSibling ->
                 emit(node.startOffset, "Declarations and declarations with comments should have an empty space between.", true)
@@ -59,7 +59,7 @@
             }
     }
 
-    private fun ASTNode.isBlankLine() = isWhiteSpace20 && text.startsWith("\n\n")
+    private fun ASTNode.isBlankLine() = isWhiteSpace && text.startsWith("\n\n")
 }
 
 public val SPACING_BETWEEN_DECLARATIONS_WITH_COMMENTS_RULE_ID: RuleId = SpacingBetweenDeclarationsWithCommentsRule().ruleId
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenFunctionNameAndOpeningParenthesisRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenFunctionNameAndOpeningParenthesisRule.kt
index b172cd6..3466dc1 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenFunctionNameAndOpeningParenthesisRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/SpacingBetweenFunctionNameAndOpeningParenthesisRule.kt
@@ -8,8 +8,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -24,8 +24,8 @@
         node
             .takeIf { node.elementType == FUN }
             ?.findChildByType(IDENTIFIER)
-            ?.nextSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.nextSibling
+            ?.takeIf { it.isWhiteSpace }
             ?.let { whiteSpace ->
                 emit(whiteSpace.startOffset, "Unexpected whitespace", true)
                     .ifAutocorrectAllowed { whiteSpace.remove() }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StatementWrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StatementWrappingRule.kt
index af49fdf..50a297e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StatementWrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StatementWrappingRule.kt
@@ -20,16 +20,16 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasModifier
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.indent
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
 import com.pinterest.ktlint.rule.engine.core.api.noNewLineInClosedRange
 import com.pinterest.ktlint.rule.engine.core.api.parent
@@ -158,7 +158,7 @@
             takeIf { elementType == FUNCTION_LITERAL }
                 ?.takeUnless { it.textContains('\n') }
                 ?.findChildByType(BLOCK)
-                ?.children20
+                ?.children
                 ?.count { it.elementType != VALUE_PARAMETER_LIST && it.elementType != ARROW }
                 ?.let { count -> count <= 1 }
                 ?: false
@@ -166,7 +166,7 @@
     private inline val ASTNode.isEnumClassOnSingleLine: Boolean
         get() =
             if (isEnumClass) {
-                val lastChildLeaf = lastChildLeafOrSelf20
+                val lastChildLeaf = lastChildLeafOrSelf
                 // Ignore the leading comment
                 noNewLineInClosedRange(firstCodeLeafOrNull!!, lastChildLeaf)
             } else {
@@ -177,31 +177,31 @@
         get() =
             // Skip the comment on top of the node by getting modifier list
             findChildByType(MODIFIER_LIST)
-                ?.children20
+                ?.children
                 ?.dropWhile {
                     // Ignore annotations placed on separate lines above the node
-                    it.elementType == ANNOTATION_ENTRY || it.isWhiteSpace20
+                    it.elementType == ANNOTATION_ENTRY || it.isWhiteSpace
                 }?.firstOrNull()
-                ?.firstChildLeafOrSelf20
+                ?.firstChildLeafOrSelf
 
     private inline val ASTNode.isEnumClass: Boolean
         get() = elementType == CLASS && hasModifier(ENUM_KEYWORD)
 
     private inline val ASTNode.indentAsChild: String
-        get() = indent20.plus(indentConfig.indent)
+        get() = indent.plus(indentConfig.indent)
 
     private inline val ASTNode.indentAsSibling: String
-        get() = parent!!.indent20.plus(indentConfig.indent)
+        get() = parent!!.indent.plus(indentConfig.indent)
 
     private inline val ASTNode.indentAsParent: String
-        get() = parent!!.indent20
+        get() = parent!!.indent
 
     private fun visitSemiColon(
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        val previousCodeLeaf = node.prevCodeLeaf?.lastChildLeafOrSelf20 ?: return
-        val nextCodeLeaf = node.nextCodeLeaf?.firstChildLeafOrSelf20 ?: return
+        val previousCodeLeaf = node.prevCodeLeaf?.lastChildLeafOrSelf ?: return
+        val nextCodeLeaf = node.nextCodeLeaf?.firstChildLeafOrSelf ?: return
         if (previousCodeLeaf.parent?.elementType == ENUM_ENTRY && nextCodeLeaf.elementType == RBRACE) {
             // Allow
             // enum class INDEX2 { ONE, TWO, THREE; }
@@ -210,7 +210,7 @@
         if (noNewLineInClosedRange(previousCodeLeaf, nextCodeLeaf)) {
             emit(node.startOffset + 1, """Missing newline after '${node.text}'""", true)
                 .ifAutocorrectAllowed {
-                    node.upsertWhitespaceAfterMe(previousCodeLeaf.indent20)
+                    node.upsertWhitespaceAfterMe(previousCodeLeaf.indent)
                 }
         }
     }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateIndentRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateIndentRule.kt
index c16e862..ca56ec6 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateIndentRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateIndentRule.kt
@@ -22,18 +22,17 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -104,10 +103,10 @@
                         }
                     stringTemplate
                         .getFirstLeafAfterTrimIndent()
-                        ?.takeUnless { it.isWhiteSpaceWithNewline20 }
+                        ?.takeUnless { it.isWhiteSpaceWithNewline }
                         ?.takeUnless { it.elementType == COMMA }
                         ?.takeUnless { it.parent?.elementType == DOT_QUALIFIED_EXPRESSION }
-                        ?.takeUnless { it.parent?.elementType == BINARY_EXPRESSION && it.nextSibling20?.elementType == OPERATION_REFERENCE }
+                        ?.takeUnless { it.parent?.elementType == BINARY_EXPRESSION && it.nextSibling?.elementType == OPERATION_REFERENCE }
                         ?.let { nextLeaf ->
                             emit(nextLeaf.startOffset, "Expected newline after multiline string template", true)
                                 .ifAutocorrectAllowed {
@@ -137,10 +136,10 @@
         takeIf { it.elementType == STRING_TEMPLATE }
             ?.takeIf { it.isFollowedByTrimIndent() }
             ?.parent
-            ?.lastChildLeafOrSelf20
+            ?.lastChildLeafOrSelf
             ?.nextLeaf
 
-    private fun ASTNode.isPrecededByWhitespaceWithNewline() = prevLeaf.isWhiteSpaceWithNewline20
+    private fun ASTNode.isPrecededByWhitespaceWithNewline() = prevLeaf.isWhiteSpaceWithNewline
 
     private fun ASTNode.isPrecededByReturnKeyword() =
         // Allow below as otherwise it results in compilation failure:
@@ -154,7 +153,7 @@
             ?.takeIf { it.elementType == EQ }
             ?.closingParenthesisOfFunctionOrNull()
             ?.prevLeaf
-            ?.isWhiteSpaceWithNewline20
+            ?.isWhiteSpaceWithNewline
             ?: false
 
     private fun ASTNode.closingParenthesisOfFunctionOrNull() =
@@ -167,7 +166,7 @@
         // is out of scope of this rule as it is owned by the indentation rule. Therefore, the indentation of the line at which the
         // string template is found, is assumed to be correct and is used to indent all lines of the string template. The indent will be
         // fixed once the indent rule is run as well.
-        val firstWhiteSpaceLeafOnSameLine = this.prevLeaf { it.isWhiteSpaceWithNewline20 }
+        val firstWhiteSpaceLeafOnSameLine = this.prevLeaf { it.isWhiteSpaceWithNewline }
         return if (prevLeaf == firstWhiteSpaceLeafOnSameLine) {
             // The string template already is on a separate new line. Keep the current indent.
             firstWhiteSpaceLeafOnSameLine.getTextAfterLastNewline()
@@ -238,7 +237,7 @@
         checkAndFixNewLineAfterOpeningQuotes(node, newIndent, emit)
 
         node
-            .children20
+            .children
             .filterNot { it.elementType == OPEN_QUOTE }
             .filterNot {
                 // Blank lines inside the string template should not be indented
@@ -335,7 +334,7 @@
                         LeafPsiElement(REGULAR_STRING_PART, newIndent),
                     )
                 } else {
-                    node.firstChildLeafOrSelf20.replaceTextWith(newIndent + newContent)
+                    node.firstChildLeafOrSelf.replaceTextWith(newIndent + newContent)
                 }
             }
     }
@@ -361,7 +360,7 @@
 
     private fun ASTNode.containsLiteralStringTemplateEntryWithNewline(): Boolean {
         require(elementType == STRING_TEMPLATE)
-        return children20
+        return children
             .any { it.elementType == LITERAL_STRING_TEMPLATE_ENTRY && it.text == "\n" }
     }
 
@@ -399,7 +398,7 @@
         )
     }
 
-    private fun ASTNode.isIndentBeforeClosingQuote() = text.isBlank() && nextCodeSibling20?.elementType == CLOSING_QUOTE
+    private fun ASTNode.isIndentBeforeClosingQuote() = text.isBlank() && nextCodeSibling?.elementType == CLOSING_QUOTE
 
     private companion object {
         const val RAW_STRING_LITERAL_QUOTES = "\"\"\""
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateRule.kt
index 684f669..cca7a84 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/StringTemplateRule.kt
@@ -18,12 +18,12 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -78,7 +78,7 @@
 
     private fun ASTNode.splitCodeChildren(): Triple<ASTNode, ASTNode, ASTNode> {
         require(elementType == DOT_QUALIFIED_EXPRESSION)
-        return children20
+        return children
             .filter { it.isCode }
             .toList()
             .also { require(it.size == 3) }
@@ -89,11 +89,11 @@
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         takeIf { it.isStringTemplate() }
-            ?.children20
+            ?.children
             ?.firstOrNull { it.elementType != LONG_TEMPLATE_ENTRY_START }
             ?.takeIf { it.elementType == REFERENCE_EXPRESSION || it.elementType == THIS_EXPRESSION }
             ?.let {
-                nextSibling20
+                nextSibling
                     ?.takeIf { nextSibling ->
                         nextSibling.elementType == CLOSING_QUOTE ||
                             (
@@ -101,7 +101,7 @@
                                     !nextSibling.text.substring(0, 1).isPartOfIdentifier()
                             )
                     }?.let {
-                        emit(prevSibling20!!.startOffset + 2, "Redundant curly braces", true)
+                        emit(prevSibling!!.startOffset + 2, "Redundant curly braces", true)
                             .ifAutocorrectAllowed { removeCurlyBracesIfRedundant() }
                     }
             }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ThenSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ThenSpacingRule.kt
index 78f171f..d50174d 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ThenSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ThenSpacingRule.kt
@@ -5,13 +5,13 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.endOffset20
+import com.pinterest.ktlint.rule.engine.core.api.endOffset
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -35,18 +35,18 @@
         emit: (Int, String, Boolean) -> AutocorrectDecision,
     ) {
         node
-            .takeUnless { it.prevSibling20.isWhiteSpace20 }
+            .takeUnless { it.prevSibling.isWhiteSpace }
             ?.let {
                 emit(node.startOffset, "Expected a whitespace before 'then' block", true)
                     .ifAutocorrectAllowed { node.prevLeaf?.upsertWhitespaceAfterMe(" ") }
             }
         node
-            .takeUnless { it.nextSibling20 == null || it.nextSibling20.isWhiteSpace20 }
+            .takeUnless { it.nextSibling == null || it.nextSibling.isWhiteSpace }
             ?.let {
                 node
-                    .lastChildLeafOrSelf20
+                    .lastChildLeafOrSelf
                     .let { lastLeafInThen ->
-                        emit(lastLeafInThen.endOffset20, "Expected a whitespace after 'then' block", true)
+                        emit(lastLeafInThen.endOffset, "Expected a whitespace after 'then' block", true)
                             .ifAutocorrectAllowed { lastLeafInThen.upsertWhitespaceAfterMe(" ") }
                     }
             }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnCallSiteRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnCallSiteRule.kt
index 43f9b05..de043cb 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnCallSiteRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnCallSiteRule.kt
@@ -15,17 +15,16 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfigProperty
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -74,7 +73,7 @@
     ) {
         val inspectNode =
             node
-                .children20
+                .children
                 .last { it.elementType == RBRACKET }
         node.reportAndCorrectTrailingCommaNodeBefore(
             inspectNode = inspectNode,
@@ -91,7 +90,7 @@
     ) {
         val inspectNode =
             node
-                .children20
+                .children
                 .last { it.elementType == RBRACKET }
         node.reportAndCorrectTrailingCommaNodeBefore(
             inspectNode = inspectNode,
@@ -106,7 +105,7 @@
     ) {
         if (node.parent?.elementType != FUNCTION_LITERAL) {
             node
-                .children20
+                .children
                 .lastOrNull { it.elementType == RPAR }
                 ?.let { inspectNode ->
                     node.reportAndCorrectTrailingCommaNodeBefore(
@@ -124,7 +123,7 @@
     ) {
         val inspectNode =
             node
-                .children20
+                .children
                 .first { it.elementType == GT }
         node.reportAndCorrectTrailingCommaNodeBefore(
             inspectNode = inspectNode,
@@ -165,8 +164,8 @@
                         true,
                     ).ifAutocorrectAllowed {
                         inspectNode
-                            .prevCodeSibling20
-                            ?.nextSibling20
+                            .prevCodeSibling
+                            ?.nextSibling
                             ?.let { before ->
                                 before.parent?.addChild(LeafPsiElement(COMMA, ","), before)
                             }
@@ -201,9 +200,9 @@
     private fun ASTNode.findValueArgumentFollowedByWhiteSpaceWithNewline() =
         this
             .findChildByType(VALUE_ARGUMENT)
-            ?.nextSibling { it.isWhiteSpaceWithNewline20 }
+            ?.nextSibling { it.isWhiteSpaceWithNewline }
 
-    private fun ASTNode.hasAtLeastOneArgument() = children20.any { it.elementType == VALUE_ARGUMENT }
+    private fun ASTNode.hasAtLeastOneArgument() = children.any { it.elementType == VALUE_ARGUMENT }
 
     private fun ASTNode.findPreviousTrailingCommaNodeOrNull(): ASTNode? {
         val codeLeaf =
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnDeclarationSiteRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnDeclarationSiteRule.kt
index 68f5927..b493dc4 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnDeclarationSiteRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TrailingCommaOnDeclarationSiteRule.kt
@@ -27,16 +27,16 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfigProperty
 import com.pinterest.ktlint.rule.engine.core.api.hasModifier
 import com.pinterest.ktlint.rule.engine.core.api.hasNewLineInClosedRange
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.isCode
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.noNewLineInClosedRange
 import com.pinterest.ktlint.rule.engine.core.api.parent
@@ -99,7 +99,7 @@
     ) {
         val inspectNode =
             node
-                .children20
+                .children
                 .last { it.elementType == RPAR }
         node.reportAndCorrectTrailingCommaNodeBefore(
             inspectNode = inspectNode,
@@ -116,7 +116,7 @@
     ) {
         val inspectNode =
             node
-                .children20
+                .children
                 .lastOrNull { it.elementType == ARROW }
                 ?: // lambda w/o an arrow -> no arguments -> no commas
                 return
@@ -133,7 +133,7 @@
     ) {
         if (node.parent?.elementType != FUNCTION_LITERAL) {
             node
-                .children20
+                .children
                 .lastOrNull { it.elementType == RPAR }
                 ?.let { inspectNode ->
                     node.reportAndCorrectTrailingCommaNodeBefore(
@@ -151,7 +151,7 @@
     ) {
         val inspectNode =
             node
-                .children20
+                .children
                 .first { it.elementType == GT }
         node.reportAndCorrectTrailingCommaNodeBefore(
             inspectNode = inspectNode,
@@ -173,7 +173,7 @@
 
         val inspectNode =
             node
-                .children20
+                .children
                 .first { it.elementType == ARROW }
         node.reportAndCorrectTrailingCommaNodeBefore(
             inspectNode = inspectNode,
@@ -217,11 +217,12 @@
             }
     }
 
-    private fun ASTNode.noEnumEntries() = children20.none { it.elementType == ENUM_ENTRY }
+    private fun ASTNode.noEnumEntries() = children.none { it.elementType == ENUM_ENTRY }
 
     private fun ASTNode.lastTwoEnumEntriesAreOnSameLine(): Boolean {
         val lastTwoEnumEntries =
-            children20
+            this@lastTwoEnumEntriesAreOnSameLine
+                .children
                 .filter { it.elementType == ENUM_ENTRY }
                 .toList()
                 .takeLast(2)
@@ -236,9 +237,9 @@
      * last element of the class.
      */
     private fun ASTNode.findNodeAfterLastEnumEntry() =
-        children20
+        children
             .lastOrNull { it.elementType == ENUM_ENTRY }
-            ?.children20
+            ?.children
             ?.singleOrNull { it.elementType == SEMICOLON }
             ?: lastChildNode
 
@@ -273,13 +274,13 @@
                         ?.findChildByType(ARROW)
                         ?.prevLeaf
                         ?.let { lastNodeBeforeArrow ->
-                            if (!lastNodeBeforeArrow.isWhiteSpaceWithNewline20) {
+                            if (!lastNodeBeforeArrow.isWhiteSpaceWithNewline) {
                                 emit(
                                     trailingCommaNode!!.startOffset,
                                     "Expected a newline between the trailing comma and  \"${inspectNode.text}\"",
                                     true,
                                 ).ifAutocorrectAllowed {
-                                    lastNodeBeforeArrow.upsertWhitespaceAfterMe(inspectNode.parent!!.indent20)
+                                    lastNodeBeforeArrow.upsertWhitespaceAfterMe(inspectNode.parent!!.indent)
                                 }
                             }
                         }
@@ -295,7 +296,7 @@
             TrailingCommaState.MISSING -> {
                 if (isTrailingCommaAllowed) {
                     val leafBeforeArrowOrNull = leafBeforeArrowOrNull()
-                    val addNewLine = !(leafBeforeArrowOrNull?.isWhiteSpaceWithNewline20 ?: true)
+                    val addNewLine = !(leafBeforeArrowOrNull?.isWhiteSpaceWithNewline ?: true)
                     val prevNode = inspectNode.prevCodeLeaf!!
                     if (addNewLine) {
                         emit(
@@ -311,8 +312,8 @@
                         )
                     }.ifAutocorrectAllowed {
                         if (addNewLine) {
-                            val indent = prevNode.parent!!.indent20
-                            if (leafBeforeArrowOrNull.isWhiteSpace20) {
+                            val indent = prevNode.parent!!.indent
+                            if (leafBeforeArrowOrNull.isWhiteSpace) {
                                 leafBeforeArrowOrNull.replaceTextWith(indent)
                             } else {
                                 inspectNode
@@ -326,8 +327,8 @@
 
                         if (inspectNode.parent?.elementType == ENUM_ENTRY) {
                             val parentIndent =
-                                (prevNode.parent?.prevLeaf?.takeIf { it.isWhiteSpace20 })?.text
-                                    ?: prevNode.indent20
+                                (prevNode.parent?.prevLeaf?.takeIf { it.isWhiteSpace })?.text
+                                    ?: prevNode.indent
                             inspectNode
                                 .parent
                                 ?.apply {
@@ -416,7 +417,7 @@
 
     private fun ASTNode.hasWhenEntryGuard() = elementType == WHEN_ENTRY && hasWhenEntryGuardKotlin21()
 
-    private fun ASTNode.hasWhenEntryGuardKotlin21(): Boolean = children20.any { it.elementType == WHEN_ENTRY_GUARD }
+    private fun ASTNode.hasWhenEntryGuardKotlin21(): Boolean = children.any { it.elementType == WHEN_ENTRY_GUARD }
 
     private enum class TrailingCommaState {
         /**
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TryCatchFinallySpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TryCatchFinallySpacingRule.kt
index 70e1489..a11c2de 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TryCatchFinallySpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TryCatchFinallySpacingRule.kt
@@ -18,7 +18,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
@@ -58,7 +58,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isPartOfComment20 && node.parent?.elementType in TRY_CATCH_FINALLY_TOKEN_SET) {
+        if (node.isPartOfComment && node.parent?.elementType in TRY_CATCH_FINALLY_TOKEN_SET) {
             emit(node.startOffset, "No comment expected at this location", false)
             return
         }
@@ -84,7 +84,7 @@
         node
             .findChildByType(LBRACE)!!
             .let { lbrace ->
-                val nextSibling = lbrace.nextSibling { !it.isPartOfComment20 }!!
+                val nextSibling = lbrace.nextSibling { !it.isPartOfComment }!!
                 if (!nextSibling.text.startsWith("\n")) {
                     emit(lbrace.startOffset + 1, "Expected a newline after '{'", true)
                         .ifAutocorrectAllowed {
@@ -96,7 +96,7 @@
         node
             .findChildByType(RBRACE)!!
             .let { rbrace ->
-                val prevSibling = rbrace.prevSibling { !it.isPartOfComment20 }!!
+                val prevSibling = rbrace.prevSibling { !it.isPartOfComment }!!
                 if (!prevSibling.text.startsWith("\n")) {
                     emit(rbrace.startOffset, "Expected a newline before '}'", true)
                         .ifAutocorrectAllowed {
@@ -110,7 +110,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        val prevLeaf = node.prevLeaf { !it.isPartOfComment20 }!!
+        val prevLeaf = node.prevLeaf { !it.isPartOfComment }!!
         if (prevLeaf.text != " ") {
             emit(node.startOffset, "A single space is required before '${node.elementTypeName()}'", true)
                 .ifAutocorrectAllowed {
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentCommentRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentCommentRule.kt
index cc8c073..3328e02 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentCommentRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentCommentRule.kt
@@ -8,8 +8,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -29,7 +29,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isPartOfComment20 && node.parent?.elementType in typeArgumentTokenSet) {
+        if (node.isPartOfComment && node.parent?.elementType in typeArgumentTokenSet) {
             when (node.elementType) {
                 EOL_COMMENT, BLOCK_COMMENT -> {
                     if (node.parent?.elementType == TYPE_PROJECTION) {
@@ -44,7 +44,7 @@
                             false,
                         )
                     } else if (node.parent?.elementType == TYPE_ARGUMENT_LIST) {
-                        if (node.prevLeaf.isWhiteSpaceWithNewline20) {
+                        if (node.prevLeaf.isWhiteSpaceWithNewline) {
                             // Allow:
                             //     fun Foo<
                             //         /* some comment */
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentListSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentListSpacingRule.kt
index 59df90d..0107295 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentListSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeArgumentListSpacingRule.kt
@@ -21,12 +21,12 @@
 import com.pinterest.ktlint.rule.engine.core.api.findParentByType
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
@@ -116,11 +116,11 @@
 
         node
             .findChildByType(LT)
-            ?.nextSibling20
+            ?.nextSibling
             ?.let { nextSibling ->
                 if (multiline) {
                     if (nextSibling.text != expectedIndent) {
-                        if (nextSibling.isWhiteSpaceWithoutNewline20) {
+                        if (nextSibling.isWhiteSpaceWithoutNewline) {
                             emit(nextSibling.startOffset, "Expected newline", true)
                                 .ifAutocorrectAllowed {
                                     nextSibling.upsertWhitespaceAfterMe(expectedIndent)
@@ -130,7 +130,7 @@
                         }
                     }
                 } else {
-                    if (nextSibling.isWhiteSpace20) {
+                    if (nextSibling.isWhiteSpace) {
                         // Disallow
                         //    val list = listOf< String>()
                         noWhitespaceExpected(nextSibling, emit)
@@ -140,11 +140,11 @@
 
         node
             .findChildByType(GT)
-            ?.prevSibling20
+            ?.prevSibling
             ?.let { prevSibling ->
                 if (multiline) {
                     if (prevSibling.text != expectedIndent) {
-                        if (prevSibling.isWhiteSpaceWithoutNewline20) {
+                        if (prevSibling.isWhiteSpaceWithoutNewline) {
                             emit(prevSibling.startOffset, "Expected newline", true)
                                 .ifAutocorrectAllowed {
                                     prevSibling.upsertWhitespaceBeforeMe(expectedIndent)
@@ -154,7 +154,7 @@
                         }
                     }
                 } else {
-                    if (prevSibling.isWhiteSpace20) {
+                    if (prevSibling.isWhiteSpace) {
                         // Disallow
                         //    val list = listOf<String >()
                         noWhitespaceExpected(prevSibling, emit)
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterCommentRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterCommentRule.kt
index c704c2a..2e5c044 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterCommentRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterCommentRule.kt
@@ -8,8 +8,8 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -29,7 +29,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isPartOfComment20 && node.parent?.elementType in typeParameterTokenSet) {
+        if (node.isPartOfComment && node.parent?.elementType in typeParameterTokenSet) {
             when (node.elementType) {
                 EOL_COMMENT, BLOCK_COMMENT -> {
                     if (node.parent?.elementType == TYPE_PARAMETER) {
@@ -44,7 +44,7 @@
                             false,
                         )
                     } else if (node.parent?.elementType == TYPE_PARAMETER_LIST) {
-                        if (node.prevLeaf.isWhiteSpaceWithNewline20) {
+                        if (node.prevLeaf.isWhiteSpaceWithNewline) {
                             // Allow
                             //     class Foo<
                             //         /* some comment */
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterListSpacingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterListSpacingRule.kt
index 8ebc8cf..917b568 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterListSpacingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/TypeParameterListSpacingRule.kt
@@ -20,15 +20,15 @@
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextSibling
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.rule.engine.core.api.replaceTextWith
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
@@ -82,19 +82,19 @@
         // No white space expected between class name and parameter list
         //     class Bar <T>
         node
-            .prevSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            .prevSibling
+            ?.takeIf { it.isWhiteSpace }
             ?.let { visitWhitespace(it, emit) }
 
         // No white space expected between parameter type list and the constructor except when followed by compound
         // constructor
         //     class Bar<T> (...)
         node
-            .nextSibling20
-            ?.takeIf { it.isWhiteSpace20 && it.nextCodeSibling20?.elementType == PRIMARY_CONSTRUCTOR }
+            .nextSibling
+            ?.takeIf { it.isWhiteSpace && it.nextCodeSibling?.elementType == PRIMARY_CONSTRUCTOR }
             ?.let { whiteSpace ->
-                if (whiteSpace.nextCodeSibling20?.findChildByType(CONSTRUCTOR_KEYWORD) != null) {
-                    if (whiteSpace.isWhiteSpaceWithNewline20) {
+                if (whiteSpace.nextCodeSibling?.findChildByType(CONSTRUCTOR_KEYWORD) != null) {
+                    if (whiteSpace.isWhiteSpaceWithNewline) {
                         // Newline is acceptable before (modifier list of) constructor
                         //    class Bar<T>
                         //        constructor(...)
@@ -132,8 +132,8 @@
         // No white space expected between parameter type list and class body when constructor is missing
         //    class Bar<T> {
         node
-            .nextSibling20
-            ?.takeIf { it.isWhiteSpace20 && it.nextCodeSibling20?.elementType == CLASS_BODY }
+            .nextSibling
+            ?.takeIf { it.isWhiteSpace && it.nextCodeSibling?.elementType == CLASS_BODY }
             ?.let { singleSpaceExpected(it, emit) }
     }
 
@@ -144,15 +144,15 @@
         // No white space expected between typealias keyword name and parameter list
         //     typealias Bar <T>
         node
-            .prevSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            .prevSibling
+            ?.takeIf { it.isWhiteSpace }
             ?.let { visitWhitespace(it, emit) }
 
         // No white space expected between parameter type list and equals sign
         //    typealias Bar<T> = ...
         node
-            .nextSibling20
-            ?.takeIf { it.isWhiteSpace20 && it.nextCodeSibling20?.elementType == EQ }
+            .nextSibling
+            ?.takeIf { it.isWhiteSpace && it.nextCodeSibling?.elementType == EQ }
             ?.let { singleSpaceExpected(it, emit) }
     }
 
@@ -165,7 +165,7 @@
         node
             .prevLeaf
             ?.let { prevLeaf ->
-                if (prevLeaf.isWhiteSpace20) {
+                if (prevLeaf.isWhiteSpace) {
                     singleSpaceExpected(prevLeaf, emit)
                 } else {
                     singleSpaceExpected(node.firstChildNode, emit)
@@ -189,8 +189,8 @@
     ) {
         node
             .findChildByType(LT)
-            ?.nextSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.nextSibling
+            ?.takeIf { it.isWhiteSpace }
             ?.let {
                 val expectedWhitespace =
                     if (node.textContains('\n')) {
@@ -203,8 +203,8 @@
 
         node
             .findChildByType(GT)
-            ?.prevSibling20
-            ?.takeIf { it.isWhiteSpace20 }
+            ?.prevSibling
+            ?.takeIf { it.isWhiteSpace }
             ?.let {
                 val expectedWhitespace =
                     if (node.textContains('\n')) {
@@ -231,7 +231,7 @@
                     .ifAutocorrectAllowed { node.remove() }
             }
 
-            node.isWhiteSpaceWithoutNewline20 && expectedWhitespace.startsWith("\n") -> {
+            node.isWhiteSpaceWithoutNewline && expectedWhitespace.startsWith("\n") -> {
                 emit(node.startOffset, "Expected a newline", true)
                     .ifAutocorrectAllowed { node.replaceTextWith(expectedWhitespace) }
             }
@@ -252,7 +252,7 @@
                 Unit
             }
 
-            node.isWhiteSpaceWithNewline20 -> {
+            node.isWhiteSpaceWithNewline -> {
                 emit(node.startOffset, "Expected a single space instead of newline", true)
                     .ifAutocorrectAllowed { node.replaceTextWith(" ") }
             }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRule.kt
index 3a26a5e..5bbc57a 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRule.kt
@@ -12,11 +12,11 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.remove
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -34,8 +34,8 @@
         if (node.isEmptyArgumentList() &&
             node.isPartOf(CALL_EXPRESSION) &&
             node.isNotPrecededByCallExpressionEndingWithLambdaArgument() &&
-            node.nextCodeSibling20?.elementType == LAMBDA_ARGUMENT &&
-            node.prevCodeSibling20?.elementType != CALL_EXPRESSION
+            node.nextCodeSibling?.elementType == LAMBDA_ARGUMENT &&
+            node.prevCodeSibling?.elementType != CALL_EXPRESSION
         ) {
             emit(
                 node.startOffset,
@@ -47,12 +47,12 @@
 
     private fun ASTNode.isEmptyArgumentList(): Boolean =
         elementType == VALUE_ARGUMENT_LIST &&
-            children20
+            children
                 .filterNot { it.elementType == LPAR || it.elementType == RPAR }
                 .none()
 
     private fun ASTNode.isNotPrecededByCallExpressionEndingWithLambdaArgument() =
-        prevCodeSibling20
+        prevCodeSibling
             ?.takeIf { it.elementType == CALL_EXPRESSION }
             ?.lastChildNode
             ?.takeIf { it.elementType == LAMBDA_ARGUMENT }
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueArgumentCommentRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueArgumentCommentRule.kt
index 9f2617c..9e6be44 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueArgumentCommentRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueArgumentCommentRule.kt
@@ -5,7 +5,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -23,7 +23,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isPartOfComment20 && node.parent?.elementType == VALUE_ARGUMENT) {
+        if (node.isPartOfComment && node.parent?.elementType == VALUE_ARGUMENT) {
             // Disallow:
             //     val foo = foo(
             //         bar /* some comment */ = "bar"
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueParameterCommentRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueParameterCommentRule.kt
index cc96ef4..e1f482e 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueParameterCommentRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/ValueParameterCommentRule.kt
@@ -6,7 +6,7 @@
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -24,7 +24,7 @@
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isPartOfComment20 && node.parent?.elementType == VALUE_PARAMETER) {
+        if (node.isPartOfComment && node.parent?.elementType == VALUE_PARAMETER) {
             if (node.elementType == KDOC && node.parent?.firstChildNode == node) {
                 // Allow KDoc to be the first element of a value parameter. EOL and block comments directly before a value parameter are
                 // a child of the value parameter list, and as of that will never be the first child of the value.
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WhenEntryBracing.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WhenEntryBracing.kt
index cef94a0..115c702 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WhenEntryBracing.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WhenEntryBracing.kt
@@ -12,19 +12,18 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.EXPERIMENTAL
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.parent
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
+import com.pinterest.ktlint.rule.engine.core.api.prevSibling
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.psi.psiUtil.leaves
@@ -77,7 +76,7 @@
         }
     }
 
-    private fun ASTNode.hasAnyWhenEntryWithBlockAfterArrow() = children20.any { it.elementType == WHEN_ENTRY && it.hasBlockAfterArrow() }
+    private fun ASTNode.hasAnyWhenEntryWithBlockAfterArrow() = children.any { it.elementType == WHEN_ENTRY && it.hasBlockAfterArrow() }
 
     private fun ASTNode.hasBlockAfterArrow(): Boolean {
         require(elementType == WHEN_ENTRY)
@@ -87,14 +86,14 @@
             .any { it.elementType == BLOCK }
     }
 
-    private fun ASTNode.hasAnyWhenEntryWithMultilineBody() = children20.any { it.elementType == WHEN_ENTRY && it.hasMultilineBody() }
+    private fun ASTNode.hasAnyWhenEntryWithMultilineBody() = children.any { it.elementType == WHEN_ENTRY && it.hasMultilineBody() }
 
     private fun ASTNode.hasMultilineBody(): Boolean {
         require(elementType == WHEN_ENTRY)
         return findChildByType(ARROW)
             ?.siblings()
             .orEmpty()
-            .any { it.isWhiteSpaceWithNewline20 }
+            .any { it.isWhiteSpaceWithNewline }
     }
 
     private fun addBracesToWhenEntry(
@@ -102,14 +101,14 @@
         emitAndApprove: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
         node
-            .children20
+            .children
             .filter { it.elementType == WHEN_ENTRY }
             .filter { !it.hasBlockAfterArrow() }
             .forEach { whenEntry ->
                 whenEntry
                     .findChildByType(ARROW)
                     ?.let { arrow ->
-                        val nonWhiteSpaceSibling = arrow.nextSibling { !it.isWhiteSpace20 } ?: arrow
+                        val nonWhiteSpaceSibling = arrow.nextSibling { !it.isWhiteSpace } ?: arrow
                         emitAndApprove(
                             nonWhiteSpaceSibling.startOffset,
                             "Body of when entry should be surrounded by braces if any when entry body is surrounded by braces " +
@@ -129,23 +128,23 @@
         val whenEntryIndent = indentConfig.parentIndentOf(this).removePrefix("\n")
         val whenEntry = parent!!
         // Find the anchor node, e.g. the last node before the current when-entry which is not altered
-        val siblingBeforeWhenEntry = whenEntry.prevSibling20!!
+        val siblingBeforeWhenEntry = whenEntry.prevSibling!!
         // Find the first leaf after the when-entry (including the EOL comment after it) that not has to be enclosed within the braces
         val stopLeaf =
             siblingBeforeWhenEntry
                 .siblings()
-                .takeWhile { !it.isWhiteSpaceWithNewline20 }
+                .takeWhile { !it.isWhiteSpaceWithNewline }
                 .last()
-                .nextSibling20!!
-                .firstChildLeafOrSelf20
+                .nextSibling!!
+                .firstChildLeafOrSelf
         val whenEntryNode =
             createWhenEntryNode(
-                "${whenEntryIndent}${prevCodeSibling20!!.text} -> {" +
+                "${whenEntryIndent}${prevCodeSibling!!.text} -> {" +
                     // Replace the whitespaces (possibly this could be a proper indent) at the beginning of the body with an indent. In case
                     // the body was already a multiline statement, then the second and following lines should already be properly indented.
                     indentConfig.childIndentOf(this) +
                     leaves()
-                        .dropWhile { it.isWhiteSpace20 }
+                        .dropWhile { it.isWhiteSpace }
                         .takeWhile { it != stopLeaf }
                         .joinToString(separator = "") { it.text } +
                     "\n$whenEntryIndent}",
diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WrappingRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WrappingRule.kt
index 2366341..97ad5cc 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WrappingRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/WrappingRule.kt
@@ -48,35 +48,33 @@
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint
 import com.pinterest.ktlint.rule.engine.core.api.SinceKtlint.Status.STABLE
 import com.pinterest.ktlint.rule.engine.core.api.TokenSets
-import com.pinterest.ktlint.rule.engine.core.api.children20
+import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.EditorConfig
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_SIZE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.INDENT_STYLE_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.editorconfig.MAX_LINE_LENGTH_PROPERTY_OFF
-import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.firstChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.hasNewLineInClosedRange
 import com.pinterest.ktlint.rule.engine.core.api.hasNoMaxLineLengthSuppression
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
-import com.pinterest.ktlint.rule.engine.core.api.indent20
+import com.pinterest.ktlint.rule.engine.core.api.indent
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
-import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline20
-import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline20
-import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf20
+import com.pinterest.ktlint.rule.engine.core.api.isPartOfComment
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpace
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
+import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
 import com.pinterest.ktlint.rule.engine.core.api.leavesForwardsIncludingSelf
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
 import com.pinterest.ktlint.rule.engine.core.api.nextSibling
-import com.pinterest.ktlint.rule.engine.core.api.nextSibling20
 import com.pinterest.ktlint.rule.engine.core.api.parent
 import com.pinterest.ktlint.rule.engine.core.api.prevCodeLeaf
-import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling20
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
 import com.pinterest.ktlint.rule.engine.core.api.prevSibling
-import com.pinterest.ktlint.rule.engine.core.api.prevSibling20
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceAfterMe
 import com.pinterest.ktlint.rule.engine.core.api.upsertWhitespaceBeforeMe
 import com.pinterest.ktlint.ruleset.standard.StandardRule
@@ -162,7 +160,7 @@
         }
 
         node
-            .takeUnless { it.firstChildLeafOrSelf20.elementType == EOL_COMMENT }
+            .takeUnless { it.firstChildLeafOrSelf.elementType == EOL_COMMENT }
             ?.getEndOfBlock()
             ?.takeIf { it.elementType == RBRACE }
             ?.let { rbrace ->
@@ -175,13 +173,13 @@
             val lengthUntilBeginOfLine =
                 node
                     .leaves(false)
-                    .takeWhile { !it.isWhiteSpaceWithNewline20 }
+                    .takeWhile { !it.isWhiteSpaceWithNewline }
                     .sumOf { it.textLength }
             val lengthUntilEndOfLine =
                 node
-                    .firstChildLeafOrSelf20
+                    .firstChildLeafOrSelf
                     .leavesForwardsIncludingSelf
-                    .takeWhile { !it.isWhiteSpaceWithNewline20 }
+                    .takeWhile { !it.isWhiteSpaceWithNewline }
                     .sumOf { it.textLength }
             if (lengthUntilBeginOfLine + lengthUntilEndOfLine > maxLineLength) {
                 requireNewlineAfterLeaf(lbrace, emit)
@@ -192,13 +190,13 @@
     private fun ASTNode.followedByEolComment() =
         null !=
             leaves()
-                .takeWhile { it.isWhiteSpaceWithoutNewline20 || it.elementType == EOL_COMMENT }
+                .takeWhile { it.isWhiteSpaceWithoutNewline || it.elementType == EOL_COMMENT }
                 .firstOrNull { it.elementType == EOL_COMMENT }
 
     private fun ASTNode.followedByFunctionLiteralParameterList() =
         VALUE_PARAMETER_LIST ==
             takeIf { parent?.elementType == FUNCTION_LITERAL }
-                ?.nextCodeSibling20
+                ?.nextCodeSibling
                 ?.elementType
 
     private fun rearrangeBlock(
@@ -260,10 +258,10 @@
                 .nextCodeLeaf
                 ?.prevLeaf {
                     // Skip comments, whitespace, and empty nodes
-                    !it.isPartOfComment20 &&
-                        !it.isWhiteSpaceWithoutNewline20 &&
+                    !it.isPartOfComment &&
+                        !it.isWhiteSpaceWithoutNewline &&
                         it.textLength > 0
-                }.isWhiteSpaceWithNewline20 &&
+                }.isWhiteSpaceWithNewline &&
             // IDEA quirk:
             // if (true &&
             //     true
@@ -275,11 +273,11 @@
             //     true
             // ) {
             // }
-            node.nextSibling20?.elementType != CONDITION
+            node.nextSibling?.elementType != CONDITION
         ) {
             requireNewlineAfterLeaf(node, emit)
         }
-        if (!closingElement.prevLeaf.isWhiteSpaceWithNewline20) {
+        if (!closingElement.prevLeaf.isWhiteSpaceWithNewline) {
             requireNewlineBeforeLeaf(closingElement, emit, indentConfig.parentIndentOf(node))
         }
     }
@@ -310,25 +308,25 @@
             )
         ) {
             // put space after :
-            if (!node.prevLeaf.isWhiteSpaceWithNewline20) {
+            if (!node.prevLeaf.isWhiteSpaceWithNewline) {
                 val colon = node.prevCodeLeaf!!
                 if (
-                    !colon.prevLeaf.isWhiteSpaceWithNewline20 &&
-                    colon.prevCodeLeaf.let { it?.elementType != RPAR || !it.prevLeaf.isWhiteSpaceWithNewline20 }
+                    !colon.prevLeaf.isWhiteSpaceWithNewline &&
+                    colon.prevCodeLeaf.let { it?.elementType != RPAR || !it.prevLeaf.isWhiteSpaceWithNewline }
                 ) {
                     requireNewlineAfterLeaf(colon, emit)
                 }
             }
             // put entries on separate lines
-            for (c in node.children20) {
+            for (c in node.children) {
                 if (c.elementType == COMMA &&
-                    !c.nextSibling20.isWhiteSpaceWithNewline20 &&
+                    !c.nextSibling.isWhiteSpaceWithNewline &&
                     !c.isFollowedByCommentOnSameLine()
                 ) {
                     requireNewlineAfterLeaf(
                         nodeAfterWhichNewlineIsRequired = c,
                         emit = emit,
-                        indent = node.indent20,
+                        indent = node.indent,
                     )
                 }
             }
@@ -336,14 +334,14 @@
     }
 
     private fun ASTNode.isFollowedByCommentOnSameLine() =
-        nextLeaf { !it.isWhiteSpaceWithoutNewline20 }
-            ?.isPartOfComment20 == true
+        nextLeaf { !it.isWhiteSpaceWithoutNewline }
+            ?.isPartOfComment == true
 
     private fun rearrangeValueList(
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        for (c in node.children20) {
+        for (c in node.children) {
             val hasLineBreak =
                 when (c.elementType) {
                     VALUE_ARGUMENT -> c.hasLineBreak(LAMBDA_EXPRESSION, FUN)
@@ -364,25 +362,25 @@
                 // c, d
 
                 // insert \n in front of multi-line value
-                val prevSibling = c.prevSibling { !it.isWhiteSpace20 }
+                val prevSibling = c.prevSibling { !it.isWhiteSpace }
                 if (
                     prevSibling?.elementType == COMMA &&
-                    !prevSibling.nextSibling20.isWhiteSpaceWithNewline20
+                    !prevSibling.nextSibling.isWhiteSpaceWithNewline
                 ) {
                     requireNewlineAfterLeaf(prevSibling, emit)
                 }
                 // insert \n after multi-line value
-                val nextSibling = c.nextSibling { !it.isWhiteSpace20 }
+                val nextSibling = c.nextSibling { !it.isWhiteSpace }
                 val hasDestructuringDeclarationAsLastValueParameter =
                     c.isLastValueParameter() && c.firstChildNode.elementType == DESTRUCTURING_DECLARATION
                 if (
                     nextSibling?.elementType == COMMA &&
                     !hasDestructuringDeclarationAsLastValueParameter &&
-                    !nextSibling.nextSibling20.isWhiteSpaceWithNewline20 &&
+                    !nextSibling.nextSibling.isWhiteSpaceWithNewline &&
                     // value(
                     // ), // a comment
                     // c, d
-                    nextSibling.nextSibling20?.nextSibling20?.let { !TokenSets.COMMENTS.contains(it.elementType) } != false
+                    nextSibling.nextSibling?.nextSibling?.let { !TokenSets.COMMENTS.contains(it.elementType) } != false
                 ) {
                     requireNewlineAfterLeaf(nextSibling, emit)
                 }
@@ -401,13 +399,13 @@
         if (node.textContains('\n')) {
             // Each type projection must be preceded with a whitespace containing a newline
             node
-                .children20
+                .children
                 .filter { it.elementType == TYPE_PROJECTION || it.elementType == TYPE_PARAMETER }
                 .forEach { typeProjection ->
                     typeProjection
-                        .prevSibling { !it.isPartOfComment20 }
+                        .prevSibling { !it.isPartOfComment }
                         .let { prevSibling ->
-                            if (prevSibling?.elementType == LT || prevSibling.isWhiteSpaceWithoutNewline20) {
+                            if (prevSibling?.elementType == LT || prevSibling.isWhiteSpaceWithoutNewline) {
                                 emit(typeProjection.startOffset, "A newline was expected before '${typeProjection.text}'", true)
                                     .ifAutocorrectAllowed {
                                         typeProjection.upsertWhitespaceBeforeMe(indentConfig.siblingIndentOf(node))
@@ -420,8 +418,8 @@
             node
                 .findChildByType(GT)
                 ?.let { closingAngle ->
-                    val prevSibling = closingAngle.prevSibling { !it.isPartOfComment20 }
-                    if (!prevSibling.isWhiteSpaceWithNewline20) {
+                    val prevSibling = closingAngle.prevSibling { !it.isPartOfComment }
+                    if (!prevSibling.isWhiteSpaceWithNewline) {
                         emit(closingAngle.startOffset, "A newline was expected before '${closingAngle.text}'", true)
                             .ifAutocorrectAllowed {
                                 closingAngle.upsertWhitespaceBeforeMe(indentConfig.siblingIndentOf(node))
@@ -441,7 +439,7 @@
             ?.let { it.psi as KtStringTemplateExpression }
             ?.takeIf { it.isMultiLine() }
             ?.takeIf { it.isFollowedByTrimIndent() || it.isFollowedByTrimMargin() }
-            ?.takeUnless { node.prevSibling20?.text.isNullOrBlank() }
+            ?.takeUnless { node.prevSibling?.text.isNullOrBlank() }
             ?.let {
                 // rewriting
                 // """
@@ -473,8 +471,8 @@
         //     find matching rToken
         //     return true if there is no newline after the rToken
         // return false
-        val nextCodeSibling = node.nextCodeSibling20 // e.g. BINARY_EXPRESSION
-        var lToken = nextCodeSibling?.nextLeaf { it.isWhiteSpaceWithNewline20 }?.prevCodeLeaf
+        val nextCodeSibling = node.nextCodeSibling // e.g. BINARY_EXPRESSION
+        var lToken = nextCodeSibling?.nextLeaf { it.isWhiteSpaceWithNewline }?.prevCodeLeaf
         if (lToken != null && lToken.elementType !in LTOKEN_SET) {
             // special cases:
             // x = y.f({ z ->
@@ -517,16 +515,16 @@
             //     0x200D // Zero-width Joiner
             //     -> true
             // }
-            (parent.elementType == WHEN_ENTRY && node.prevLeaf.isWhiteSpaceWithNewline20)
+            (parent.elementType == WHEN_ENTRY && node.prevLeaf.isWhiteSpaceWithNewline)
         ) {
             return
         }
-        if (!node.nextCodeLeaf?.prevLeaf.isWhiteSpaceWithNewline20) {
+        if (!node.nextCodeLeaf?.prevLeaf.isWhiteSpaceWithNewline) {
             requireNewlineAfterLeaf(node, emit)
         }
         val r = node.nextSibling { it.elementType == RBRACE } ?: return
-        if (!r.prevLeaf.isWhiteSpaceWithNewline20) {
-            requireNewlineBeforeLeaf(r, emit, node.indent20)
+        if (!r.prevLeaf.isWhiteSpaceWithNewline) {
+            requireNewlineBeforeLeaf(r, emit, node.indent)
         }
     }
 
@@ -569,7 +567,7 @@
     }
 
     private fun KtStringTemplateExpression.isMultiLine(): Boolean {
-        for (child in node.children20) {
+        for (child in node.children) {
             if (child.elementType == LITERAL_STRING_TEMPLATE_ENTRY) {
                 val v = child.text
                 if (v == "\n") {
@@ -581,12 +579,12 @@
     }
 
     private fun ASTNode.hasLineBreak(vararg ignoreElementTypes: IElementType): Boolean {
-        if (isWhiteSpaceWithNewline20) return true
+        if (isWhiteSpaceWithNewline) return true
         return if (ignoreElementTypes.isEmpty()) {
             textContains('\n')
         } else {
             elementType !in ignoreElementTypes &&
-                children20.any { c -> c.textContains('\n') && c.elementType !in ignoreElementTypes }
+                children.any { c -> c.textContains('\n') && c.elementType !in ignoreElementTypes }
         }
     }
 
@@ -627,10 +625,10 @@
 
         var node: ASTNode? = this
         while (node != null && node.elementType != RPAR) {
-            if (node.isWhiteSpaceWithNewline20) {
+            if (node.isWhiteSpaceWithNewline) {
                 return false
             }
-            node = node.nextSibling20
+            node = node.nextSibling
         }
         return true
     }
@@ -661,22 +659,22 @@
         }
     }
 
-    private fun ASTNode.followedByNewline() = nextLeaf.isWhiteSpaceWithNewline20
+    private fun ASTNode.followedByNewline() = nextLeaf.isWhiteSpaceWithNewline
 
-    private fun ASTNode.isPrecededByNewline() = prevLeaf.isWhiteSpaceWithNewline20
+    private fun ASTNode.isPrecededByNewline() = prevLeaf.isWhiteSpaceWithNewline
 
     private fun ASTNode.getStartOfBlock() =
         if (parent?.elementType == FUNCTION_LITERAL) {
             parent!!.findChildByType(LBRACE)
         } else {
-            firstChildLeafOrSelf20
+            firstChildLeafOrSelf
                 .let { node ->
                     if (node.elementType == LBRACE) {
                         // WHEN-entry block have LBRACE and RBRACE as first and last elements
                         node
                     } else {
                         // Other blocks have LBRACE and RBRACE as siblings of the block
-                        node.prevCodeSibling20
+                        node.prevCodeSibling
                     }
                 }
         }
@@ -685,14 +683,14 @@
         if (parent?.elementType == FUNCTION_LITERAL) {
             parent!!.findChildByType(RBRACE)
         } else {
-            lastChildLeafOrSelf20
+            lastChildLeafOrSelf
                 .let { node ->
                     if (node.elementType == RBRACE) {
                         // WHEN-entry block have LBRACE and RBRACE as first and last elements
                         node
                     } else {
                         // Other blocks have LBRACE and RBRACE as siblings of the block
-                        node.nextCodeSibling20
+                        node.nextCodeSibling
                     }
                 }
         }
diff --git a/ktlint-test/src/main/kotlin/com/pinterest/ktlint/test/KtLintAssertThat.kt b/ktlint-test/src/main/kotlin/com/pinterest/ktlint/test/KtLintAssertThat.kt
index 459cfb0..49d7aa4 100644
--- a/ktlint-test/src/main/kotlin/com/pinterest/ktlint/test/KtLintAssertThat.kt
+++ b/ktlint-test/src/main/kotlin/com/pinterest/ktlint/test/KtLintAssertThat.kt
@@ -340,31 +340,6 @@
             )
 
         /**
-         * Creates an assertThat assertion function for the rule provided by [provider]. This assertion function has extensions specifically
-         * for testing KtLint rules. The rules provided via [additionalRuleProviders] are only executed during the format phase of the test.
-         * This means that the unit test only has to check the lint violations thrown by the rule for which the assertThat is created. But
-         * the code is formatted by both the rule and the rules provided by [additionalRuleProviders] in the order as defined by the rule
-         * definitions.
-         *
-         * Use function [assertThatRule] to create a default assertThat assertion function. In case a more specialized assertion function is
-         * needed, then use [assertThatRuleBuilder].
-         */
-        @Deprecated(message = "Marked for removal in Ktlint 2.0. See KDOC for alternative")
-        public fun assertThatRule(
-            provider: () -> RuleV2,
-            additionalRuleProviders: Set<RuleV2InstanceProvider> = emptySet(),
-            editorConfigProperties: Set<Pair<EditorConfigProperty<*>, *>> = emptySet(),
-        ): (String) -> KtLintAssertThat =
-            { code ->
-                KtLintAssertThat(
-                    ruleProvider = RuleV2InstanceProvider { provider() },
-                    code = code,
-                    additionalRuleProviders = additionalRuleProviders.toMutableSet(),
-                    editorConfigProperties = editorConfigProperties.toMutableSet(),
-                )
-            }
-
-        /**
          * See [setMaxLineLength] for intended usage.
          */
         public const val MAX_LINE_LENGTH_MARKER: String = "Max line length marker:"