diff --git a/CHANGES.rst b/CHANGES.rst
index 36b46b3a5d..1b36ee39e3 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -3,6 +3,9 @@ Version 2.3.2
 
 Unreleased
 
+-   Session cookie sets ``Vary: Cookie`` header when it is accessed, modified, cleared,
+    or refreshed.
+
 
 Version 2.3.1
 -------------