diff --git a/CHANGES.rst b/CHANGES.rst
index 95638bb7906ddfb39aea92fe3d20ec7149f180ed_Q0hBTkdFUy5yc3Q=..a27759ddf5d472732d69db0e2cff0e873406b9f6_Q0hBTkdFUy5yc3Q= 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -35,6 +35,9 @@
   (such as MS-Windows).  Generating the C code on Python 3.x is recommended in this case.
   Original patches by Inada Naoki and Victor Stinner.  (Github issues #3677, #3721, #3697)
 
+* Some template parameters were missing from the C++ ``std::unordered_map`` declaration.
+  Patch by will.  (Github issue #3685)
+
 * Several internal code generation issues regarding temporary variables were resolved.
   (Github issue #3708)