Added changelog entries for the sync.
diff --git a/CHANGES.txt b/CHANGES.txt
index 76910c4..8c1bc2f 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,38 @@
+Unreleased Changes
+
+ Protocol Compiler
+ * The proto compiler no longer requires a .proto filename when it is not
+ generating code.
+
+ C++
+ * Arenas are now unconditionally enabled. cc_enable_arenas no longer has
+ any effect.
+ * Fix a memory corruption bug in reflection when mixing optional and
+ non-optional fields.
+ * Make SpaceUsed() calculation more thorough for map fields.
+ * Add stack overflow protection for text format with unknown field values.
+ * FieldPath::FollowAll() now returns a bool to signal if an out-of-bounds
+ error was encountered.
+ * Performance improvements for Map.
+ * Minor formatting fix when dumping a descriptor to .proto format with
+ DebugString.
+ * UBSAN fix in RepeatedField (#2073).
+ * When running under ASAN, skip a test that makes huge allocations.
+ * Fixed a crash that could happen when creating more than 256 extensions in
+ a single message.
+
+ Java
+ * Bugfix in mergeFrom() when a oneof has multiple message fields.
+
+ Python
+ * Print google.protobuf.NullValue as null instead of "NULL_VALUE" when it is
+ used outside WKT Value/Struct.
+ * Fix bug occurring when attempting to deep copy an enum type in python 3.
+
+ Go:
+ * Update go_package options to reference google.golang.org/protobuf module.
+
+
2020-07-14 version 3.13.0-rc1 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
C++:
