diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index 4fb79b9d40b..2e23653a064 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -7,6 +7,7 @@
 .. moduleauthor:: Mike Verdone <mike.verdone@gmail.com>
 .. moduleauthor:: Mark Russell <mark.russell@zen.co.uk>
 .. sectionauthor:: Benjamin Peterson
+.. versionadded:: 2.6
 
 The :mod:`io` module provides the Python interfaces to stream handling.  The
 builtin :func:`open` function is defined in this module.