in theory this should not cause backward compatibility issues since the
disallowed command forms didn't make any sense and are unlikely to be in use.
+* The :func:`re.split`, :func:`re.findall`, and :func:`re.sub` functions, and
+ the :meth:`~re.match.group` and :meth:`~re.match.groups` methods of
+ :class:``match`` objects now always return a *bytes* object when the string
+ to be matched is a :term:`bytes-like object`. Previously the return type
+ matched the input type, so if your code was depending on the return value
+ being, say, a ``bytearray``, you will need to change your code.
+
Changes in the C API
--------------------