Python 3.13.0RC2, 3.12.6, 3.11.10, 3.10.15, 3.9.20, and 3.8.20 are now available!

Hi there!
A big joint release today. Mostly security fixes but we also have the final release candidate of 3.13 so let’s start with that!

Python 3.13.0RC2

Final opportunity to test and find any show-stopper bugs before we bless and release 3.13.0 final on October 1st.

Get it here: Python Release Python 3.13.0rc2 | Python.org

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 3.13.0rc2 will work with future versions of Python 3.13. As always, report any issues to the Python bug tracker.

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.

Core developers: time to work on documentation now

• Are all your changes properly documented?
• Are they mentioned in What’s New?
• Did you notice other changes you know of to have insufficient documentation?

As a reminder, until the final release of 3.13.0, the 3.13 branch is set up so that the Release Manager (@thomas) has to merge the changes. Please add him (@Yhg1s on GitHub) to any changes you think should go into 3.13.0. At this point, unless something critical comes up, it should really be documentation only. Other changes (including tests) will be pushed to 3.13.1.

New features in Python 3.13

• A new and improved interactive interpreter, based on PyPy’s, featuring multi-line editing and color support, as well as colorized exception tracebacks.
• An experimental free-threaded build mode, 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, 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, which allows debuggers to operate more consistently.
• The (cyclic) garbage collector is now incremental, which should mean shorter pauses for collection in programs with a lot of objects.
• A modified version of 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, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• The dbm module has a new dbm.sqlite3 backend 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. Emscripten is no longer an officially supported platform (but Pyodide continues to support Emscripten).
• iOS is now a Tier 3 supported platform, with Android on the way as well.

Python 3.12.6

This is an expedited release for 3.12 due to security content. The schedule returns back to regular programming in October.

One notable change for macOS users: as mentioned in the previous release of 3.12, this release drops support for macOS versions 10.9 through 10.12. Versions of macOS older than 10.13 haven’t been supported by Apple since 2019, and maintaining support for them has become too difficult. (All versions of Python 3.13 have already dropped support for them.)

Get it here: Python Release Python 3.12.6 | Python.org

92 commits.

Python 3.11.10

Python 3.11 joins the elite club of security-only versions with no binary installers.

Get it here: Python Release Python 3.11.10 | Python.org

28 commits.

Python 3.10.15

Get it here: Python Release Python 3.10.15 | Python.org

24 commits.

Python 3.9.20

Get it here: Python Release Python 3.9.20 | Python.org

22 commits.

Python 3.8.20

Python 3.8 is very close to End of Life (see the Release Schedule). Will this be the last release of 3.8 ever? We’ll see… but now I think I jinxed it.

Get it here: Python Release Python 3.8.20 | Python.org

22 commits.

Security content in today’s releases

• gh-123678 and gh-116741: Upgrade bundled libexpat to 2.6.3 to fix CVE-2024-28757, CVE-2024-45490, CVE-2024-45491 and CVE-2024-45492.
• gh-118486: os.mkdir() on Windows now accepts mode of 0o700 to restrict the new directory to the current user. This fixes CVE-2024-4030 affecting tempfile.mkdtemp() in scenarios where the base temporary directory is more permissive than the default.
• gh-123067: Fix quadratic complexity in parsing "-quoted cookie values with backslashes by http.cookies. Fixes CVE-2024-7592.
• gh-113171: Fixed various false positives and false negatives in IPv4Address.is_private, IPv4Address.is_global, IPv6Address.is_private, IPv6Address.is_global. Fixes CVE-2024-4032.
• gh-67693: Fix urllib.parse.urlunparse() and urllib.parse.urlunsplit() for URIs with path starting with multiple slashes and no authority. Fixes CVE-2015-2104.
• gh-121957: Fixed missing audit events around interactive use of Python, now also properly firing for python -i, as well as for python -m asyncio. The event in question is cpython.run_stdin.
• gh-122133: Authenticate the socket connection for the socket.socketpair() fallback on platforms where AF_UNIX is not available like Windows.
• gh-121285: Remove backtracking from tarfile header parsing for hdrcharset, PAX, and GNU sparse headers. That’s CVE-2024-6232.
• gh-114572: ssl.SSLContext.cert_store_stats() and ssl.SSLContext.get_ca_certs() now correctly lock access to the certificate store, when the ssl.SSLContext is shared across multiple threads.
• gh-102988: email.utils.getaddresses() and email.utils.parseaddr() now return ('', '') 2-tuples in more situations where invalid email addresses are encountered instead of potentially inaccurate values. Add optional strict parameter to these two functions: use strict=False to get the old behavior, accept malformed inputs. getattr(email.utils, 'supports_strict_parsing', False) can be use to check if the strict paramater is available. This improves the CVE-2023-27043 fix.
• gh-123270: Sanitize names in zipfile.Path to avoid infinite loops (gh-122905) without breaking contents using legitimate characters. That’s CVE-2024-8088.
• gh-121650: email headers with embedded newlines are now quoted on output. The generator will now refuse to serialize (write) headers that are unsafely folded or delimited; see verify_generated_headers. That’s CVE-2024-6923.
• gh-119690: Fixes data type confusion in audit events raised by _winapi.CreateFile and _winapi.CreateNamedPipe.
• gh-116773: Fix instances of <_overlapped.Overlapped object at 0xXXX> still has pending operation at deallocation, the process may crash.
• gh-112275: A deadlock involving pystate.c’s HEAD_LOCK in posixmodule.c at fork is now fixed.

Stay safe and upgrade!

Upgrading is highly recommended to all users of affected versions.

Thank you for your support

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.

–
Łukasz Langa @ambv
on behalf of your friendly release team,

Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal
Łukasz Langa @ambv
Thomas Wouters @thomas

 

 

Python 3.12.5 released

 

I'm pleased to announce the release of Python 3.12.5:

https://www.python.org/downloads/release/python-3125/

 

This is the fifth maintenance release of Python 3.12

Python 3.12 is the newest major release of the Python programming language, and it contains many new features and optimizations. 3.12.5 is the latest maintenance release, containing more than 250 bugfixes, build improvements and documentation changes since 3.12.4.

This version of Python 3.12 also comes with pip 24.2 by default. However, due to an incompatibility with older macOS versions, macOS 10.9 through 10.12 will downgrade their version of pip to 24.1.2 during the installation process (in the Install Certificates step). See the installer ReadMe and the pip issue on the matter for more information. Versions of macOS older than 10.13 haven’t been supported by Apple since 2019, and maintaining support for them is becoming increasingly difficult. While this release of 3.12 still supports them, it is likely that we will be forced to drop support for macOS 10.12 and older in a future 3.12 release. (Python 3.13 has already dropped support for them.)

 

 

Major new features of the 3.12 series, compared to 3.11

 

New features

• More flexible f-string parsing, allowing many things previously disallowed (PEP 701).
• Support for the buffer protocol in Python code (PEP 688).
• A new debugging/profiling API (PEP 669).
• Support for isolated subinterpreters with separate Global Interpreter Locks (PEP 684).
• Even more improved error messages. More exceptions potentially caused by typos now make suggestions to the user.
• Support for the Linux perf profiler to report Python function names in traces.
• Many large and small performance improvements (like PEP 709 and support for the BOLT binary optimizer), delivering an estimated 5% overall performance improvement.

Type annotations

• New type annotation syntax for generic classes (PEP 695).
• New override decorator for methods (PEP 698).

Deprecations

• The deprecated wstr and wstr_length members of the C implementation of unicode objects were removed, per PEP 623.
• In the unittest module, a number of long deprecated methods and classes were removed. (They had been deprecated since Python 3.1 or 3.2).
• The deprecated smtpd and distutils modules have been removed (see PEP 594 and PEP 632. The setuptools package continues to provide the distutils module.
• A number of other old, broken and deprecated functions, classes and methods have been removed.
• Invalid backslash escape sequences in strings now warn with SyntaxWarning instead of DeprecationWarning, making them more visible. (They will become syntax errors in the future.)
• The internal representation of integers has changed in preparation for performance enhancements. (This should not affect most users as it is an internal detail, but it may cause problems for Cython-generated code.)

For more details on the changes to Python 3.12, see What’s new in Python 3.12.

 

More resources

• Online Documentation.
• PEP 693, the Python 3.12 Release Schedule.
• Report bugs via GitHub Issues.
• Help fund Python directly or via GitHub Sponsors, and support the Python community.

 

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.

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

Python 3.13.0 release candidate 1 released

 I'm pleased to announce the release of Python 3.13 release candidate 1.

https://www.python.org/downloads/release/python-3130rc1/

 

This is the first release candidate of Python 3.13.0

This release, 3.13.0rc1, is the penultimate release preview. Entering the release candidate phase, only reviewed code changes which are clear bug fixes are allowed between this release candidate and the final release. The second candidate (and the last planned release preview) is scheduled for Tuesday, 2024-09-03, while the official release of 3.13.0 is scheduled for Tuesday, 2024-10-01.

There will be no ABI changes from this point forward in the 3.13 series, and the goal is that there will be as few code changes as possible.

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 will work with future versions of Python 3.13. As always, report any issues to the Python bug tracker.

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.

Core developers: time to work on documentation now

• Are all your changes properly documented?
• Are they mentioned in What’s New?
• Did you notice other changes you know of to have insufficient documentation?

 

Major new features of the 3.13 series, compared to 3.12

Some of the new major new features and changes in Python 3.13 are:

New features

• A new and improved interactive interpreter, based on PyPy’s, featuring multi-line editing and color support, as well as colorized exception tracebacks.
• An experimental free-threaded build mode, 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, 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, which allows debuggers to operate more consistently.
• The (cyclic) garbage collector is now incremental, which should mean shorter pauses for collection in programs with a lot of objects.
• A modified version of 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, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• The dbm module has a new dbm.sqlite3 backend 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. Emscripten is no longer an officially supported platform (but Pyodide continues to support Emscripten).
• iOS is now a Tier 3 supported platform, with Android on the way as well.

Typing

• Support for type defaults in type parameters.
• A new type narrowing annotation, typing.TypeIs.
• A new annotation for read-only items in TypeDicts.
• A new annotation for marking deprecations in the type system.

Removals and new deprecations

• PEP 594 (Removing dead batteries from the standard library) scheduled removals of many deprecated modules: aifc, audioop, chunk, cgi, cgitb, crypt, imghdr, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu, xdrlib, lib2to3.
• Many other removals of deprecated classes, functions and methods in various standard library modules.
• C API removals and deprecations. (Some removals present in alpha 1 were reverted in alpha 2, as the removals were deemed too disruptive at this time.)
• New deprecations, most of which are scheduled for removal from Python 3.15 or 3.16.

(Hey, fellow core developer, if a feature you find important is missing from this list, let Thomas know.)

For more details on the changes to Python 3.13, see What’s new in Python 3.13. The next pre-release of Python 3.13 will be 3.13.0rc2, the final release candidate, currently scheduled for 2024-09-03.

 

More resources

• Online Documentation
• PEP 719, 3.13 Release Schedule
• Report bugs at Issues · python/cpython · GitHub.
• Help fund Python directly (or via GitHub Sponsors), and support the Python community.

 

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.

Whatevs,

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

Python 3.13.0 beta 4 released

I'm pleased to announce the release of Python 3.13 beta 4.

https://www.python.org/downloads/release/python-3130b4/

 

This is a beta preview of Python 3.13

Python 3.13 is still in development. This release, 3.13.0b4, is the final beta release preview of 3.13.

Beta release previews are intended to give the wider community the opportunity to test new features and bug fixes and to prepare their projects to support the new feature release.

We strongly encourage maintainers of third-party Python projects to test with 3.13 during the beta phase and report issues found to the Python bug tracker as soon as possible. While the release is planned to be feature complete entering the beta phase, it is possible that features may be modified or, in rare cases, deleted up until the start of the release candidate phase (Tuesday 2024-07-30). Our goal is to have no ABI changes after this final beta release, and as few code changes as possible after 3.13.0rc1, the first release candidate. To achieve that, it will be extremely important to get as much exposure for 3.13 as possible during the beta phase.

Please keep in mind that this is a preview release and its use is not recommended for production environments.

 

Major new features of the 3.13 series, compared to 3.12

Some of the new major new features and changes in Python 3.13 are:

New features

• A new and improved interactive interpreter, based on PyPy’s, featuring multi-line editing and color support, as well as colorized exception tracebacks.
• An experimental free-threaded build mode, 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, 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, which allows debuggers to operate more consistently.
• The (cyclic) garbage collector is now incremental, which should mean shorter pauses for collection in programs with a lot of objects.
• A modified version of 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, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• The dbm module has a new dbm.sqlite3 backend 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. Emscripten is no longer an officially supported platform (but Pyodide continues to support Emscripten).

Typing

• Support for type defaults in type parameters.
• A new type narrowing annotation, typing.TypeIs.
• A new annotation for read-only items in TypeDicts.
• A new annotation for marking deprecations in the type system.

Removals and new deprecations

• PEP 594 (Removing dead batteries from the standard library) scheduled removals of many deprecated modules: aifc, audioop, chunk, cgi, cgitb, crypt, imghdr, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu, xdrlib, lib2to3.
• Many other removals of deprecated classes, functions and methods in various standard library modules.
• C API removals and deprecations. (Some removals present in alpha 1 were reverted in alpha 2, as the removals were deemed too disruptive at this time.)
• New deprecations, most of which are scheduled for removal from Python 3.15 or 3.16.

(Hey, fellow core developer, if a feature you find important is missing from this list, let Thomas know.)

For more details on the changes to Python 3.13, see What’s new in Python 3.13. The next pre-release of Python 3.13 will be 3.13.0rc1, the first release candidate, currently scheduled for 2024-07-30.

 

More resources

• Online Documentation
• PEP 719, 3.13 Release Schedule
• Report bugs at https://github.com/python/cpython/issues.
• Help fund Python directly (or via GitHub Sponsors), and support the Python community.

 

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.

 

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

Python 3.13.0 beta 3 released

 

I'm pleased to announce the release of Python 3.13 beta 3.

https://www.python.org/downloads/release/python-3130b3/

 

This is a beta preview of Python 3.13

Python 3.13 is still in development. This release, 3.13.0b3, is the third of four beta release previews of 3.13.

Beta release previews are intended to give the wider community the opportunity to test new features and bug fixes and to prepare their projects to support the new feature release.

We strongly encourage maintainers of third-party Python projects to test with 3.13 during the beta phase and report issues found to the Python bug tracker as soon as possible. While the release is planned to be feature complete entering the beta phase, it is possible that features may be modified or, in rare cases, deleted up until the start of the release candidate phase (Tuesday 2024-07-30). Our goal is to have no ABI changes after beta 4 and as few code changes as possible after 3.13.0rc1, the first release candidate. To achieve that, it will be extremely important to get as much exposure for 3.13 as possible during the beta phase.

 

Please keep in mind that this is a preview release and its use is not recommended for production environments.

 

Major new features of the 3.13 series, compared to 3.12

Some of the new major new features and changes in Python 3.13 are:

New features

• A new and improved interactive interpreter , based on PyPy’s, featuring multi-line editing and color support, as well as colorized exception tracebacks .
• An experimental free-threaded build mode , 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 , providing the ground work for significant performance improvements.
• The (cyclic) garbage collector is now incremental , which should mean shorter pauses for collection in programs with a lot of objects.
• A modified version of 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, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• The dbm module has a new dbm.sqlite3 backend 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.
  

Typing

• Support for type defaults in type parameters.
• A new type narrowing annotation , typing.TypeIs.
• A new annotation for read-only items in TypeDicts .

Removals and new deprecations

• PEP 594 (Removing dead batteries from the standard library) scheduled removals of many deprecated modules: aifc, audioop, chunk, cgi, cgitb, crypt, imghdr, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu, xdrlib, lib2to3.
• Many other removals of deprecated classes, functions and methods in various standard library modules.
• C API removals and deprecations. (Some removals present in alpha 1 were reverted in alpha 2, as the removals were deemed too disruptive at this time.)
• New deprecations, most of which are scheduled for removal from Python 3.15 or 3.16.

(Hey, fellow core developer, if a feature you find important is missing from this list, let Thomas know.)

For more details on the changes to Python 3.13, see What’s new in Python 3.13 . The next pre-release of Python 3.13 will be 3.13.0b4, currently scheduled for 2024-07-16.

 

More resources

• Online Documentation
• PEP 719 , 3.13 Release Schedule
• Report bugs at Issues · python/cpython · GitHub .
• Help fund Python directly (or via GitHub Sponsors), and support the Python community.

 

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.

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

 

Python 3.12.4 released

I'm pleased to announce the release of Python 3.12.4:

https://www.python.org/downloads/release/python-3124/

 

This is the third maintenance release of Python 3.12

Python 3.12 is the newest major release of the Python programming language, and it contains many new features and optimizations. 3.12.4 is the latest maintenance release, containing more than 250 bugfixes, build improvements and documentation changes since 3.12.3.

 

Major new features of the 3.12 series, compared to 3.11

 

New features

• More flexible f-string parsing, allowing many things previously disallowed (PEP 701).
• Support for the buffer protocol in Python code (PEP 688).
• A new debugging/profiling API (PEP 669).
• Support for isolated subinterpreters with separate Global Interpreter Locks (PEP 684).
• Even more improved error messages. More exceptions potentially caused by typos now make suggestions to the user.
• Support for the Linux perf profiler to report Python function names in traces.
• Many large and small performance improvements (like PEP 709 and support for the BOLT binary optimizer), delivering an estimated 5% overall performance improvement.

Type annotations

• New type annotation syntax for generic classes (PEP 695).
• New override decorator for methods (PEP 698).

Deprecations

• The deprecated wstr and wstr_length members of the C implementation of unicode objects were removed, per PEP 623.
• In the unittest module, a number of long deprecated methods and classes were removed. (They had been deprecated since Python 3.1 or 3.2).
• The deprecated smtpd and distutils modules have been removed (see PEP 594 and PEP 632. The setuptools package continues to provide the distutils module.
• A number of other old, broken and deprecated functions, classes and methods have been removed.
• Invalid backslash escape sequences in strings now warn with SyntaxWarning instead of DeprecationWarning, making them more visible. (They will become syntax errors in the future.)
• The internal representation of integers has changed in preparation for performance enhancements. (This should not affect most users as it is an internal detail, but it may cause problems for Cython-generated code.)

For more details on the changes to Python 3.12, see What’s new in Python 3.12.

 

More resources

• Online Documentation.
• PEP 693, the Python 3.12 Release Schedule.
• Report bugs via GitHub Issues.
• Help fund Python directly or via GitHub Sponsors, and support the Python community.

 

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.

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

Python 3.13.0 beta 2 released

I'm pleased to announce the release of Python 3.13 beta 2.

https://www.python.org/downloads/release/python-3130b2/

 

This is a beta preview of Python 3.13

Python 3.13 is still in development. This release, 3.13.0b2, is the second of four beta release previews of 3.13.

Beta release previews are intended to give the wider community the opportunity to test new features and bug fixes and to prepare their projects to support the new feature release.

We strongly encourage maintainers of third-party Python projects to test with 3.13 during the beta phase and report issues found to the Python bug tracker as soon as possible. While the release is planned to be feature complete entering the beta phase, it is possible that features may be modified or, in rare cases, deleted up until the start of the release candidate phase (Tuesday 2024-07-30). Our goal is to have no ABI changes after beta 4 and as few code changes as possible after 3.13.0rc1, the first release candidate. To achieve that, it will be extremely important to get as much exposure for 3.13 as possible during the beta phase.

Two particularly noteworthy changes in beta 2 involve the macOS installer we provide:

• The minimum supported macOS version was changed from 10.9 to 10.13 (High Sierra). Older macOS versions will not be supported going forward.
• The macOS installer package now includes an optional additional build of Python 3.13 with the experimental free-threading feature enabled. The free-threaded version, python3.13t, is separate from and co-exists with the traditional GIL-only installation. The free-threaded build is not installed by default; use the Customize option of the installer as explained in the installer readme. Since this is an experimental feature, there may be late-breaking issues found; see the free-threaded macOS build issue on GitHub for the most recent status.

Please keep in mind that this is a preview release and its use is not recommended for production environments.

 

Major new features of the 3.13 series, compared to 3.12

Some of the new major new features and changes in Python 3.13 are:

New features

• A new and improved interactive interpreter , based on PyPy’s, featuring multi-line editing and color support, as well as colorized exception tracebacks .
• An experimental free-threaded build mode , which disables the Global Interpreter Lock, allowing threads to run more concurrently.
• A preliminary, experimental JIT , providing the ground work for significant performance improvements.
• The (cyclic) garbage collector is now incremental , which should mean shorter pauses for collection in programs with a lot of objects.
• A modified version of 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, reducing memory use and the size of .pyc files. (Most tools handling docstrings already strip leading indentation.)
• The dbm module has a new dbm.sqlite3 backend that is used by default when creating new files.

Typing

• Support for type defaults in type parameters.
• A new type narrowing annotation , typing.TypeIs.
• A new annotation for read-only items in TypeDicts .

Removals and new deprecations

• PEP 594 (Removing dead batteries from the standard library) scheduled removals of many deprecated modules: aifc, audioop, chunk, cgi, cgitb, crypt, imghdr, mailcap, msilib, nis, nntplib, ossaudiodev, pipes, sndhdr, spwd, sunau, telnetlib, uu, xdrlib, lib2to3.
• Many other removals of deprecated classes, functions and methods in various standard library modules.
• C API removals and deprecations. (Some removals present in alpha 1 were reverted in alpha 2, as the removals were deemed too disruptive at this time.)
• New deprecations, most of which are scheduled for removal from Python 3.15 or 3.16.

(Hey, fellow core developer, if a feature you find important is missing from this list, let Thomas know.)

For more details on the changes to Python 3.13, see What’s new in Python 3.13 . The next pre-release of Python 3.13 will be 3.13.0b3, currently scheduled for 2024-06-25.

 

More resources

• Online Documentation
• PEP 719 , 3.13 Release Schedule
• Report bugs at Issues · python/cpython · GitHub .
• Help fund Python directly (or via GitHub Sponsors), and support the Python community.

 

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.

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