diff --git a/pytools/persistent_dict.py b/pytools/persistent_dict.py
index df9f2f5b99cf90d872a2089a1c8831a98fc40d1d..f48027fde89649a9e9ee7f6dd6d488166b4b0765 100644
--- a/pytools/persistent_dict.py
+++ b/pytools/persistent_dict.py
@@ -186,7 +186,7 @@ class KeyBuilder:
         this to create new hashes. Not doing so is deprecated and
         may stop working as early as 2022.
 
-        .. versionadded:: 2021.1.3
+        .. versionadded:: 2021.2
     """
 
     # this exists so that we can (conceivably) switch algorithms at some point