diff --git a/CHANGES.rst b/CHANGES.rst
index 11b129d..e46d912 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -13,7 +13,7 @@ The following notes provide some details on what has been revised for each
 version in reverse chronological order (most recent version at the top
 of the list).
 
-4.0.0 (unreleased)
+4.0.0 (2021-08-12)
 ------------------
 
 - Removed Python 2 support. Python 3.6 or later is now required. [#121]