diff --git a/CHANGES.txt b/CHANGES.txt
index 6234f1635d..a0335e06c1 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,3 +1,13 @@
+Unreleased Changes
+
+  C++:
+  * Enabled heterogeneous lookup for std::string keys in maps.
+  * Improved the randomness of map ordering.
+
+  Python:
+  * Improved the error message when AttributeError is returned from __getattr__
+    in EnumTypeWrapper.
+
 2020-05-12 version 3.12.0 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
 
   Protocol Compiler