The following APIs will be removed in the future, although there is currently no date scheduled for their removal.

• :mod:`argparse`:
  • Nesting argument groups and nesting mutually exclusive groups are deprecated.
  • Passing the undocumented keyword argument prefix_chars to :meth:`~argparse.ArgumentParser.add_argument_group` is now deprecated.
  • The :class:`argparse.FileType` type converter is deprecated.
• :mod:`builtins`:
  • Generators: throw(type, exc, tb) and athrow(type, exc, tb) signature is deprecated: use throw(exc) and athrow(exc) instead, the single argument signature.
  • Currently Python accepts numeric literals immediately followed by keywords, for example 0in x, 1or x, 0if 1else 2. It allows confusing and ambiguous expressions like [0x1for x in y] (which can be interpreted as [0x1 for x in y] or [0x1f or x in y]). A syntax warning is raised if the numeric literal is immediately followed by one of keywords :keyword:`and`, :keyword:`else`, :keyword:`for`, :keyword:`if`, :keyword:`in`, :keyword:`is` and :keyword:`or`. In a future release it will be changed to a syntax error. (:gh:`87999`)
  • Support for __index__() and __int__() method returning non-int type: these methods will be required to return an instance of a strict subclass of :class:`int`.
  • Passing a complex number as the real or imag argument in the :func:`complex` constructor is now deprecated; it should only be passed as a single positional argument. (Contributed by Serhiy Storchaka in :gh:`109218`.)
• :mod:`calendar`: calendar.January and calendar.February constants are deprecated and replaced by :data:`calendar.JANUARY` and :data:`calendar.FEBRUARY`. (Contributed by Prince Roshan in :gh:`103636`.)
• :mod:`codecs`: use :func:`open` instead of :func:`codecs.open`. (:gh:`133038`)
• :attr:`codeobject.co_lnotab`: use the :meth:`codeobject.co_lines` method instead.
• :mod:`datetime`:
  • :meth:`~datetime.datetime.utcnow`: use datetime.datetime.now(tz=datetime.UTC).
  • :meth:`~datetime.datetime.utcfromtimestamp`: use datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC).
• :mod:`gettext`: Plural value must be an integer.
• :mod:`importlib`:
  • :func:`~importlib.util.cache_from_source` debug_override parameter is deprecated: use the optimization parameter instead.
• :mod:`importlib.metadata`:
  • EntryPoints tuple interface.
  • Implicit None on return values.
• :mod:`logging`: the warn() method has been deprecated since Python 3.3, use :meth:`~logging.warning` instead.
• :mod:`mailbox`: Use of StringIO input and text mode is deprecated, use BytesIO and binary mode instead.
• :mod:`os`: Calling :func:`os.register_at_fork` in a multi-threaded process.
• :mod:`os.path`: :func:`os.path.commonprefix` is deprecated, use :func:`os.path.commonpath` for path prefixes. The :func:`os.path.commonprefix` function is being deprecated due to having a misleading name and module. The function is not safe to use for path prefixes despite being included in a module about path manipulation, meaning it is easy to accidentally introduce path traversal vulnerabilities into Python programs by using this function.
• :class:`!pydoc.ErrorDuringImport`: A tuple value for exc_info parameter is deprecated, use an exception instance.
• :mod:`re`: More strict rules are now applied for numerical group references and group names in regular expressions. Only sequence of ASCII digits is now accepted as a numerical reference. The group name in bytes patterns and replacement strings can now only contain ASCII letters and digits and underscore. (Contributed by Serhiy Storchaka in :gh:`91760`.)
• :mod:`shutil`: :func:`~shutil.rmtree`'s onerror parameter is deprecated in Python 3.12; use the onexc parameter instead.
• :mod:`ssl` options and protocols:
  • :class:`ssl.SSLContext` without protocol argument is deprecated.
  • :class:`ssl.SSLContext`: :meth:`~ssl.SSLContext.set_npn_protocols` and :meth:`!selected_npn_protocol` are deprecated: use ALPN instead.
  • ssl.OP_NO_SSL* options
  • ssl.OP_NO_TLS* options
  • ssl.PROTOCOL_SSLv3
  • ssl.PROTOCOL_TLS
  • ssl.PROTOCOL_TLSv1
  • ssl.PROTOCOL_TLSv1_1
  • ssl.PROTOCOL_TLSv1_2
  • ssl.TLSVersion.SSLv3
  • ssl.TLSVersion.TLSv1
  • ssl.TLSVersion.TLSv1_1
• :mod:`threading` methods:
  • :meth:`!threading.Condition.notifyAll`: use :meth:`~threading.Condition.notify_all`.
  • :meth:`!threading.Event.isSet`: use :meth:`~threading.Event.is_set`.
  • :meth:`!threading.Thread.isDaemon`, :meth:`threading.Thread.setDaemon`: use :attr:`threading.Thread.daemon` attribute.
  • :meth:`!threading.Thread.getName`, :meth:`threading.Thread.setName`: use :attr:`threading.Thread.name` attribute.
  • :meth:`!threading.currentThread`: use :meth:`threading.current_thread`.
  • :meth:`!threading.activeCount`: use :meth:`threading.active_count`.
• :class:`typing.Text` (:gh:`92332`).
• The internal class typing._UnionGenericAlias is no longer used to implement :class:`typing.Union`. To preserve compatibility with users using this private class, a compatibility shim will be provided until at least Python 3.17. (Contributed by Jelle Zijlstra in :gh:`105499`.)
• :class:`unittest.IsolatedAsyncioTestCase`: it is deprecated to return a value that is not None from a test case.
• :mod:`urllib.parse` deprecated functions: :func:`~urllib.parse.urlparse` instead
  • splitattr()
  • splithost()
  • splitnport()
  • splitpasswd()
  • splitport()
  • splitquery()
  • splittag()
  • splittype()
  • splituser()
  • splitvalue()
  • to_bytes()
• :mod:`wsgiref`: SimpleHandler.stdout.write() should not do partial writes.
• :mod:`xml.etree.ElementTree`: Testing the truth value of an :class:`~xml.etree.ElementTree.Element` is deprecated. In a future release it will always return True. Prefer explicit len(elem) or elem is not None tests instead.
• :func:`sys._clear_type_cache` is deprecated: use :func:`sys._clear_internal_caches` instead.