diff --git a/Doc/library/unittest.mock.rst b/Doc/library/unittest.mock.rst
index fd4e067..d1b18d0 100644
--- a/Doc/library/unittest.mock.rst
+++ b/Doc/library/unittest.mock.rst
@@ -2095,6 +2095,10 @@
    .. versionchanged:: 3.5
       *read_data* is now reset on each call to the *mock*.
 
+   .. versionchanged:: 3.8
+      Added :meth:`__iter__` to implementation so that iteration (such as in for
+      loops) correctly consumes *read_data*.
+
 Using :func:`open` as a context manager is a great way to ensure your file handles
 are closed properly and is becoming common::