[RELEASE] Python 3.13.0rc3 and 3.12.7 released.

This is not the release you’re looking for…

(unless you’re looking for 3.12.7.)

Because no plan survives contact with reality, instead of the actual Python
3.13.0 release we have a new Python 3.13 release candidate today. Python
3.13.0rc3 rolls back the incremental cyclic garbage collector (GC), which
was added in one of the alpha releases. The incremental GC had more
significant performance regressions in specific workloads than we expected.
Rather than try to fiddle with its details in the hope of fixing them (and
not making anything else worse) we decided to revert back to the old GC in
3.13. Work on the incremental GC will continue in 3.14. We also took the
opportunity to fix some other (rare) bugs and issues found in 3.13.0rc2. The
final release of Python 3.13.0 will now happen next week, Monday October 7th
.

In an effort to return to normalcy, we’ve also released Python 3.12..7 as
scheduled, despite the expedited release a month ago. It’s important to be
regular!
3.13.0rc3

https://www.python.org/downloads/release/python-3130rc3/

The final cut of 3.13.0 (really, honest). Besides the incremental GC revert
it contains a small number of other fixes, as well as many documentation
improvements and testsuite improvements (~145 changes in total).
<https://discuss.python.org/t/python-3-12-7-and-3-13-0rc3-released/66306#p-195069-call-to-action-3>Call
to action

We strongly encourage maintainers of third-party Python projects to prepare
their projects for 3.13 compatibilities during this phase, and where
necessary publish Python 3.13 wheels on PyPI to be ready for the final
release of 3.13.0. Any binary wheels built against Python 3.13.0rc1 and
later will work with future versions of Python 3.13. As always, report any
issues to the Python bug tracker  <https://github.com/python/cpython/issues>
.

Please keep in mind that this is a preview release and while it’s as close
to the final release as we can get it, its use is not recommended for
production environments. Next week, though!
<https://discuss.python.org/t/python-3-12-7-and-3-13-0rc3-released/66306#p-195069-new-features-in-python-313-4>New
features in Python 3.13

   - A new and improved interactive interpreter
   <https://docs.python.org/3.13/whatsnew/3.13.html#a-better-interactive-interpreter>,
   based on PyPy  <https://pypy.org/>’s, featuring multi-line editing and
   color support, as well as colorized exception tracebacks
   <https://docs.python.org/3.13/whatsnew/3.13.html#improved-error-messages>
   .
   - An *experimental* free-threaded build mode
   <https://docs.python.org/3.13/whatsnew/3.13.html#free-threaded-cpython>,
   which disables the Global Interpreter Lock, allowing threads to run more
   concurrently. The build mode is available as an experimental feature in the
   Windows and macOS installers as well.
   - A preliminary, *experimental* JIT
   <https://docs.python.org/3.13/whatsnew/3.13.html#experimental-jit-compiler>,
   providing the ground work for significant performance improvements.
   - The locals() builtin function (and its C equivalent) now has well-defined
   semantics when mutating the returned mapping
   <https://docs.python.org/3.13/whatsnew/3.13.html#defined-mutation-semantics-for-locals>,
   which allows debuggers to operate more consistently.
   - A modified version of mimalloc  <https://github.com/microsoft/mimalloc>is
   now included, optional but enabled by default if supported by the platform,
   and required for the free-threaded build mode.
   - Docstrings now have their leading indentation stripped
   <https://docs.python.org/3.13/whatsnew/3.13.html#other-language-changes>,
   reducing memory use and the size of .pyc files. (Most tools handling
   docstrings already strip leading indentation.)
   - The dbm module  <https://docs.python.org/3.13/library/dbm.html>has a
   new dbm.sqlite3 backend
   <https://docs.python.org/3.13/whatsnew/3.13.html#dbm>that is used by
   default when creating new files.
   - The minimum supported macOS version was changed from 10.9 to 10.13
   (High Sierra). Older macOS versions will not be supported going forward.
   - WASI is now a Tier 2 supported platform
   <https://peps.python.org/pep-0011/#tier-2>. Emscripten is no longer
an officially
   supported platform
   <https://peps.python.org/pep-0011/#no-longer-supported-platforms>(but
   Pyodide <https://pyodide.org/> continues to support Emscripten).
   - iOS is now a Tier 3 supported platform
   <https://peps.python.org/pep-0730/>.
   - Android is now a Tier 3 supported platform
   <https://peps.python.org/pep-0738/>as well.

<https://discuss.python.org/t/python-3-12-7-and-3-13-0rc3-released/66306#p-195069-python-3127-5>Python
3.12.7

https://www.python.org/downloads/release/python-3127/

A small release since 3.12.6 was only a month ago, but nevertheless 3.12.7
contains ~120 bug fixes, build improvements and documentation changes.
<https://discuss.python.org/t/python-3-12-7-and-3-13-0rc3-released/66306#p-195069-more-resources-6>More
resources

   - Python 3.13 Online Documentation <https://docs.python.org/3.13/>
   - PEP 719 <https://peps.python.org/pep-0719/>, Python 3.13 Release
   Schedule
   - Report bugs at Issues · python/cpython · GitHub
   <https://github.com/python/cpython/issues>.
   - Help fund Python directly
   <https://www.python.org/psf/donations/python-dev/>(or via GitHub Sponsors
   <https://github.com/sponsors/python>), and support the Python community
   <https://www.python.org/psf/donations/>.

<https://discuss.python.org/t/python-3-12-7-and-3-13-0rc3-released/66306#p-195069-enjoy-the-new-releases-7>Enjoy
the new releases

Thanks to all of the many volunteers who help make Python Development and
these releases possible! Please consider supporting our efforts by
volunteering yourself or through organization contributions to the Python
Software Foundation.

Regards from a positively *melting* Menlo Park for some reason
<https://social.coop/@Yhg1s/113051321976759729>this time,

Your release team,
Thomas Wouters
Łukasz Langa
Ned Deily
Steve Dower