diff --git a/.bazelci/presubmit.yml b/.bazelci/presubmit.yml
index 78e1d50..be62c01 100644
--- a/.bazelci/presubmit.yml
+++ b/.bazelci/presubmit.yml
@@ -44,6 +44,24 @@
       - "@rules_java//java/..."
     test_targets:
       - "//:MyTest"
+  ubuntu2004_integration_workspace:
+    name: "Bazel 7.x Integration (WORKSPACE)"
+    bazel: "7.4.0"
+    platform: ubuntu2004
+    working_directory: "test/repo"
+    shell_commands:
+      - sh setup.sh
+    build_targets:
+      - "//..."
+      - "//:bin_deploy.jar"
+    build_flags:
+      - "--noenable_bzlmod"
+      - "--enable_workspace"
+    test_targets:
+      - "//:MyTest"
+    test_flags:
+      - "--noenable_bzlmod"
+      - "--enable_workspace"
   macos:
     name: "Bazel 7.x"
     bazel: "7.4.0"
@@ -71,6 +89,24 @@
       - "@rules_java//java/..."
     test_targets:
       - "//:MyTest"
+  ubuntu2004_integration_head_workspace:
+    name: "Bazel@HEAD Integration (WORKSPACE)"
+    bazel: "last_green"
+    platform: ubuntu2004
+    working_directory: "test/repo"
+    shell_commands:
+      - sh setup.sh
+    build_targets:
+      - "//..."
+      - "//:bin_deploy.jar"
+    build_flags:
+      - "--noenable_bzlmod"
+      - "--enable_workspace"
+    test_targets:
+      - "//:MyTest"
+    test_flags:
+      - "--noenable_bzlmod"
+      - "--enable_workspace"
   macos_head:
     name: "Bazel@HEAD"
     bazel: last_green
@@ -98,7 +134,8 @@
     build_targets:
     - "//..."
     - "//:bin_deploy.jar"
-    - "-//:MyTest"
+    test_targets:
+    - "//:MyTest"
   macos_bazel6:
     name: "Bazel 6.x"
     bazel: 6.3.0
diff --git a/WORKSPACE b/WORKSPACE
index cbe4e80..49422df 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -41,6 +41,10 @@
 
 rules_java_dependencies()
 
+load("@com_google_protobuf//bazel/private:proto_bazel_features.bzl", "proto_bazel_features")  # buildifier: disable=bzl-visibility
+
+proto_bazel_features(name = "proto_bazel_features")
+
 rules_java_toolchains()
 
 load("@stardoc//:setup.bzl", "stardoc_repositories")
diff --git a/java/repositories.bzl b/java/repositories.bzl
index 3186211..60f94ef 100644
--- a/java/repositories.bzl
+++ b/java/repositories.bzl
@@ -366,9 +366,9 @@
     maybe(
         http_archive,
         name = "com_google_protobuf",
-        sha256 = "da288bf1daa6c04d03a9051781caa52aceb9163586bff9aa6cfb12f69b9395aa",
-        strip_prefix = "protobuf-27.0",
-        url = "https://github.com/protocolbuffers/protobuf/releases/download/v27.0/protobuf-27.0.tar.gz",
+        sha256 = "ce5d00b78450a0ca400bf360ac00c0d599cc225f049d986a27e9a4e396c5a84a",
+        strip_prefix = "protobuf-29.0-rc2",
+        url = "https://github.com/protocolbuffers/protobuf/releases/download/v29.0-rc2/protobuf-29.0-rc2.tar.gz",
     )
 
 def rules_cc_repo():
@@ -439,23 +439,29 @@
 load("@rules_java//java/bazel/rules:bazel_java_library.bzl", _java_library = "java_library") # copybara-use-repo-external-label
 load("@rules_java//java/bazel/rules:bazel_java_plugin.bzl", _java_plugin = "java_plugin") # copybara-use-repo-external-label
 load("@rules_java//java/bazel/rules:bazel_java_test.bzl", _java_test = "java_test") # copybara-use-repo-external-label
+load("@rules_java//java:http_jar.bzl", _http_jar = "http_jar") # copybara-use-repo-external-label
 
 java_binary = _java_binary
 java_import = _java_import
 java_library = _java_library
 java_plugin = _java_plugin
 java_test = _java_test
+
+http_jar = _http_jar
             """,
         )
     else:
         rctx.file(
             "proxy.bzl",
             """
+load("@bazel_tools//tools/build_defs/repo:http.bzl", _http_jar = "http_jar")
 java_binary = native.java_binary
 java_import = native.java_import
 java_library = native.java_library
 java_plugin = native.java_plugin
 java_test = native.java_test
+
+http_jar = _http_jar
             """,
         )
 
diff --git a/test/repo/WORKSPACE b/test/repo/WORKSPACE
index c961444..c4f22a6 100644
--- a/test/repo/WORKSPACE
+++ b/test/repo/WORKSPACE
@@ -1,3 +1,5 @@
+workspace(name = "integration_test_repo")
+
 local_repository(
     name = "rules_java",
     path = "../../",
@@ -7,4 +9,15 @@
 
 rules_java_dependencies()
 
+load("@com_google_protobuf//bazel/private:proto_bazel_features.bzl", "proto_bazel_features")  # buildifier: disable=bzl-visibility
+
+proto_bazel_features(name = "proto_bazel_features")
+
 rules_java_toolchains()
+
+load("@compatibility_proxy//:proxy.bzl", "http_jar")
+
+http_jar(
+    name = "my_jar",
+    urls = ["file:///tmp/my_jar.jar"],
+)