Updated CHANGES.txt.
diff --git a/CHANGES.txt b/CHANGES.txt
index 93ee2b8..9e6eb44 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,6 +1,17 @@
+
Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
C++
+ * Fix bug where `Descriptor::DebugString()` printed proto3 synthetic oneofs.
+ * Provide stable versions of `SortAndUnique()`.
+ * Make sure to cache proto3 optional message fields when they are cleared.
+
+ Kotlin
+ * Restrict extension setter and getter operators to non-nullable T.
+
+3.16.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
+
+ C++
* The ::pb namespace is no longer exposed due to conflicts.
* Allow MessageDifferencer::TreatAsSet() (and friends) to override previous
calls instead of crashing.
