Add versionchanged notes for PEP 380
diff --git a/Doc/reference/simple_stmts.rst b/Doc/reference/simple_stmts.rst
index d98b829..3bd0894 100644
--- a/Doc/reference/simple_stmts.rst
+++ b/Doc/reference/simple_stmts.rst
@@ -470,10 +470,13 @@
garbage collected), the generator-iterator's :meth:`close` method will be
called, allowing any pending :keyword:`finally` clauses to execute.
-When ``yield from expression`` is used, it treats the supplied expression as
+When ``yield from <expr>`` is used, it treats the supplied expression as
a subiterator, producing values from it until the underlying iterator is
exhausted.
+ .. versionchanged:: 3.3
+ Added ``yield from <expr>`` to delegate control flow to a subiterator
+
For full details of :keyword:`yield` semantics, refer to the :ref:`yieldexpr`
section.