Add a version tag for shutdown().
diff --git a/Doc/library/socketserver.rst b/Doc/library/socketserver.rst
index 51cab5e..7f4daad 100644
--- a/Doc/library/socketserver.rst
+++ b/Doc/library/socketserver.rst
@@ -158,6 +158,8 @@
 
    Tells the :meth:`serve_forever` loop to stop and waits until it does.
 
+   .. versionadded:: 2.6
+
 
 .. data:: address_family