This article explains the new features in Python 3.14, compared to 3.13.

For full details, see the :ref:`changelog <changelog>`.

• None yet.

• Remove the type, choices, and metavar parameters of :class:`!argparse.BooleanOptionalAction`. They were deprecated since 3.12.

• Remove :class:`!collections.abc.ByteString`. It had previously raised a :exc:`DeprecationWarning` since Python 3.12.

• Remove the isdst parameter from :func:`email.utils.localtime`. (Contributed by Hugo van Kemenade in :gh:`118798`.)

• Remove :mod:`itertools` support for copy, deepcopy, and pickle operations. These had previously raised a :exc:`DeprecationWarning` since Python 3.12. (Contributed by Raymond Hettinger in :gh:`101588`.)

• Remove support for passing additional keyword arguments to :class:`pathlib.Path`. In previous versions, any such arguments are ignored.
• Remove support for passing additional positional arguments to :meth:`pathlib.PurePath.relative_to` and :meth:`~pathlib.PurePath.is_relative_to`. In previous versions, any such arguments are joined onto other.

• Remove :data:`!version` and :data:`!version_info` from :mod:`sqlite3`. (Contributed by Hugo van Kemenade in :gh:`118924`.)
• Disallow using a sequence of parameters with named placeholders. This had previously raised a :exc:`DeprecationWarning` since Python 3.12; it will now raise a :exc:`sqlite3.ProgrammingError`. (Contributed by Erlend E. Aasland in :gh:`118928` and :gh:`101693`.)

• Remove :class:`!typing.ByteString`. It had previously raised a :exc:`DeprecationWarning` since Python 3.12.

• Using :data:`NotImplemented` in a boolean context will now raise a :exc:`TypeError`. It had previously raised a :exc:`DeprecationWarning` since Python 3.9. (Contributed by Jelle Zijlstra in :gh:`118767`.)

This section lists previously described changes and other bugfixes that may require changes to your code.