2.7 -> 3.1 versionchanges.
diff --git a/Doc/library/gc.rst b/Doc/library/gc.rst
index 6929a3d..9092145 100644
--- a/Doc/library/gc.rst
+++ b/Doc/library/gc.rst
@@ -151,7 +151,7 @@
       >>> gc.is_tracked({"a": []})
       True
 
-   .. versionadded:: 2.7
+   .. versionadded:: 3.1
 
 
 The following variable is provided for read-only access (you can mutate its