Fix versionchanged.
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index 951e19c..2a3445c 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -621,7 +621,7 @@
    Named tuple instances do not have per-instance dictionaries, so they are
    lightweight and require no more memory than regular tuples.
 
-   .. versionchanged:: 2.7
+   .. versionchanged:: 3.1
       added support for *rename*.
 
 Example: