diff --git a/Doc/library/unittest.mock.rst b/Doc/library/unittest.mock.rst
index ebfaf7d..e92f554 100644
--- a/Doc/library/unittest.mock.rst
+++ b/Doc/library/unittest.mock.rst
@@ -915,6 +915,7 @@
   >>> mock.async_foo
   <AsyncMock name='mock.async_foo' id='...'>
 
+  .. versionadded:: 3.8
 
   .. method:: assert_awaited()