Python Insider

The last Python 3.11 alpha (3.11.0a7) is available

2022-04-06T06:33:00.002-04:00

Brrrrr… do you feel that? That’s the chill of beta freeze coming closer. Meanwhile, your friendly CPython release team doesn’t rest and we have prepared a shiny new release for you: Python 3.11.0a7.

https://www.python.org/downloads/release/python-3110a7/

Major new features of the 3.11 series, compared to 3.10

Among the new major new features and changes so far:

PEP 657 – Include Fine-Grained Error Locations in Tracebacks
PEP 654 – Exception Groups and except*
PEP 673 – Self Type
PEP 646 – Variadic Generics
PEP 680– tomllib: Support for Parsing TOML in the Standard Library
PEP 675– Arbitrary Literal String Type
PEP 655– Marking individual TypedDict items as required or potentially-missing
bpo-46752– Introduce task groups to asyncio
The Faster Cpython Project is already yielding some exciting results: this version of CPython 3.11 is ~19% faster on the geometric mean of the performance benchmarks, compared to 3.10.0.

(Hey,

fellow core developer,

if a feature you find important is missing from this list,

let Pablo know

The next pre-release of Python 3.11 will be 3.11.0b1, currently scheduled for Friday, 2022-05-06.

More resources

Online Documentation

PEP 664, 3.11 Release Schedule
Report bugs at https://bugs.python.org.

Help fund Python and its community.

And now for something completely different

In mathematics, the Dirac delta distribution (δ distribution) is a generalized function or distribution over the real numbers, whose value is zero everywhere except at zero, and whose integral over the entire real line is equal to one. The current understanding of the impulse is as a linear functional that maps every continuous function to its value at zero. The delta function was introduced by physicist Paul Dirac as a tool for the normalization of state vectors. It also has uses in probability theory and signal processing. Its validity was disputed until Laurent Schwartz developed the theory of distributions where it is defined as a linear form acting on functions.

Defining this distribution as a “function” as many physicist do is known to be one of the easier ways to annoy mathematicians :)

We hope you 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.

https://www.python.org/psf/

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal

Python 3.10.4 and 3.9.12 are now available out of schedule

2022-03-24T08:08:00.000-04:00

Did anybody say cursed releases? Well, it turns out that 3.10.3 and 3.9.11 both shipped a regression which caused those versions not to build on Red Hat Enterprise Linux 6. While this 11-year-old version is now out of maintenance support, it’s still used in production workloads. Some of those rely on Python 3.9 and/or 3.10. In particular, our own manylinux2010 image used to build widely compatible Linux wheels is based on CentOS 6. (Don’t worry, we do have newer manylinux* variants, see PEP 599 and PEP 600 for details.)

Due to the out-of-schedule release, the respective versions released today contain a very limited set of changes. Python 3.9.12 only contains 12 other bug fixes on top of 3.9.11. Python 3.10.4 only contains 10 other bug fixes on top of 3.10.3.

Get 3.10.4 here: Python Release Python 3.10.4 | Python.org
Get 3.9.12 here: Python Release Python 3.9.12 | Python.org

Hopefully, the third time’s a charm and we’ll return no sooner than May with the regularly scheduled bug fix releases of 3.9 and 3.10.

We hope you enjoy the new releases

Your friendly release team,
Łukasz Langa @ambv
Pablo Galindo Salgado @pablogsal
Ned Deily @nad
Steve Dower @steve.dower

Python 3.10.3, 3.9.11, 3.8.13, and 3.7.13 are now available with security content

2022-03-16T11:55:00.000-04:00

Welcome again to the exciting world of releasing new Python versions!

Last time around I was complaining about cursed releases. This time around I could complain about security content galore and how one of them ruined my ingenious idea to release Python on Pi Day and call it Py Day. Well, you can’t have everything in life. Or at least not everything at once.

And yet it seems this time around we’ve got a lot of security fixes all at once. Just look at this list:

15 (sic!) CVEs: libexpat upgraded from 2.4.1 to 2.4.7 (BPO-46794, BPO-46932, BPO-46811, BPO-46784, BPO-46400)
CVE-2022-0778: OpenSSL upgraded from 1.1.1l to 1.1.1n in macOS and Windows installers (BPO-47024)
CVE-2016-3189, CVE-2019-12900: bzip2 upgraded from 1.0.6 to 1.0.8 in Windows installers (BPO-44549)
CVE-2022-26488: Windows installer now ensures the correct path is being repaired when “Add to PATH” is used (BPO-46948)
CVE-2021-28363: bundled pip upgraded from 21.2.4 to 22.0.4 (BPO-46985)
authorization bypass fixed in urllib.request (BPO-46756)
REDoS avoided in importlib.metadata (BPO-46474)
SQLite upgraded from 3.36.0 to 3.37.2 in macOS and Windows installers (BPO-45925)

Python 3.10.3

Get it here: https://www.python.org/downloads/release/python-3103/

Python 3.10.3 is the third maintenance release of the newest version of the Python programming language, which contains many new features and optimizations. We recommend it over the other releases listed below.

This is a large bugfix release with 220 commits since 3.10.2. Just look at the change log!

The next maintenance release of Python 3.10 is planned for early June.

Python 3.9.11

Get it here: https://www.python.org/downloads/release/python-3911/

This is the penultimate planned full bugfix release of Python 3.9. In mid-May, we’ll be releasing the last one, after which the 3.9 series will enter its security-only fixes period. More details in PEP 596.

Python 3.9 is the first Python version since 2.7 to have a regular bugfix release larger than “.10”. It’s also still a significant release at 163 commits since 3.9.10. That’s in fact 30+ commits more than between 3.9.9 and 3.9.10. The change log isn’t as long as the 3.10.3 one but it’s still pretty extensive!

As a reminder, on macOS, the default installer is now the new universal2 variant. It’s compatible with Mac OS X 10.9 and newer, including macOS 11 Big Sur and macOS 12 Monterey. Python installed with this variant will work natively on Apple Silicon processors.

Python 3.8.13

Get it here: https://www.python.org/downloads/release/python-3813/

Changes here are almost exclusively security-only as the life cycle of Python versions prescribes. You might have noticed there is a small number of regular bug fixes nonetheless. This is because without those we wouldn’t be able to continue running the full test suite for the 3.8 branch. This in turn could hide regressions in future security fixes.

Python 3.7.13

Get it here: https://www.python.org/downloads/release/python-3713/

Just like 3.8, Python 3.7 is in its security-only fixes period. In turn, the changes in 3.7.13 look almost identical to the ones in 3.8.13.

Python 3.7 will continue to receive source-only releases until June 2023.

We hope you enjoy the new releases

Your friendly release team,
Łukasz Langa @ambv
Pablo Galindo Salgado @pablogsal
Ned Deily @nad
Steve Dower @steve.dower

Python 3.11.0a6 is available

2022-03-07T13:33:00.004-05:00

There are no easy releases these days! :sweat: After a week of delay due to several release blockers, buildbot problems and pandemic-related difficulties here is 3.11.0a6 for you to test.

https://www.python.org/downloads/release/python-3110a6/

Major new features of the 3.11 series, compared to 3.10

Among the new major new features and changes so far:

PEP 657 – Include Fine-Grained Error Locations in Tracebacks
PEP 654 – Exception Groups and except*
PEP 673 – Self Type
PEP 646 – Variadic Generics
The Faster Cpython Project is already yielding some exciting results: this version of CPython 3.11 is ~19% faster on the geometric mean of the performance benchmarks, compared to 3.10.0.

(Hey,

fellow core developer,

if a feature you find important is missing from this list,

let Pablo know

The next pre-release of Python 3.11 will be 3.11.0a7, currently scheduled for Tuesday, 2022-04-05.

More resources

Online Documentation

PEP 664, 3.11 Release Schedule
Report bugs at https://bugs.python.org.

Help fund Python and its community.

And now for something completely different

In astrophysics and nuclear physics, nuclear pasta is a theoretical type of degenerate matter that is postulated to exist within the crusts of neutron stars. If it does in fact exist, nuclear pasta is the strongest material in the universe. Between the surface of a neutron star and the quark-gluon plasma at the core, at matter densities of 1014 g/cm3, nuclear attraction and Coulomb repulsion forces are of similar magnitude. The competition between the forces leads to the formation of a variety of complex structures assembled from neutrons and protons. Astrophysicists call these types of structures nuclear pasta because the geometry of the structures resembles various types of pasta.

There are several phases of evolution (I swear these names are real), including the gnocchi phase, the spaghetti phase, the lasagna phase, the bucatini phase and the Swiss cheese phase.

We hope you enjoy the new releases!

https://www.python.org/psf/

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal

Python 3.11.0a5 is available

2022-02-03T18:22:00.002-05:00

We needed to tame some angry buildbots, but after a small fight, we won with just some scratches! Here you have a shiny new alpha release: Python 3.11.0a5.

https://www.python.org/downloads/release/python-3110a5/

Major new features of the 3.11 series, compared to 3.10

Among the new major new features and changes so far:

PEP 657 – Include Fine-Grained Error Locations in Tracebacks
PEP 654 – Exception Groups and except*
PEP 673 – Self Type
PEP 646 – Variadic Generics
The Faster Cpython Project is already yielding some exciting results: this version of CPython 3.11 is ~19% faster on the geometric mean of the performance benchmarks, compared to 3.10.0.

(Hey,

fellow core developer,

if a feature you find important is missing from this list,

let Pablo know

The next pre-release of Python 3.11 will be 3.11.0a6, currently scheduled for Monday, 2022-02-28.

More resources

Online Documentation

PEP 664, 3.11 Release Schedule
Report bugs at https://bugs.python.org.

Help fund Python and its community.

And now for something completely different

In physics, the Poynting vector (Umov-Poynting vector) represents the directional energy flux (the energy transfer per unit area per unit time) or power flow of an electromagnetic field. It is named after its discoverer John Henry Poynting who first derived it in 1884. Oliver Heaviside also discovered it independently in the more general form that recognises the freedom of adding the curl of an arbitrary vector field to the definition. The Poynting vector is used throughout electromagnetics in conjunction with Poynting's theorem, the continuity equation expressing conservation of electromagnetic energy, to calculate the power flow in electromagnetic fields.

We hope you enjoy the new releases!

https://www.python.org/psf/

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal

Python 3.10.2, 3.9.10, and 3.11.0a4 are now available

2022-01-14T18:11:00.001-05:00

Before we begin the usual round of release notes, please do note that the three new versions of Python released today do not contain Windows installers yet. This is temporary, due to a more complex than expected code signing certificate renewal.

We’ve held the releases all week while the situation is getting resolved but the urgency of 3.10.2 in particular made us release without the Windows installers after all. We apologize for the inconvenience and are doing everything we can to put the Windows installer in place as soon as possible.

We’re rooting for both Ee Durbin and Steve Dower who are helping us resolve this. Thanks for your hard work! Hopefully, by this time next week, this will only be a footnote in release management history.

The releases you’re looking at were all cursed in some way. What a way to start 2022! Besides the certificate hold up, Python 3.10.2 is an expedited release (you’ll want to upgrade, read below!), Python 3.11.0a4 had almost 20 (sic, twenty!) release blockers before being finally green, and Python 3.9.10 was made from a new M1 Mac on macOS Monterey which made the usually boring process quite a ride. We’re hoping 2022 won’t be this intense all year!

Python 3.10.2

Get it here: https://www.python.org/downloads/release/python-3102/

This is a special bugfix release ahead of schedule to address a memory leak that was happening on certain function calls when using Cython. The memory leak consisted of a small constant amount of bytes in certain function calls from Cython code. Although in most cases this was not very noticeable, it was very impactful for long-running applications and certain usage patterns. Check bpo-46347 for more information.

Upgrading existing Python 3.10 installations is highly recommended. Even though this is an expedited release, it still contains over 100 other bug fixes. See the change log for details.

The next Python 3.10 maintenance release will be 3.10.3, currently scheduled for 2022-04-04.

Python 3.9.10

Get it here: https://www.python.org/downloads/release/python-3910/

Python 3.9.10 is the ninth maintenance release of the legacy 3.9 series. Note: Python 3.10 is now the latest feature release series of Python 3.

Python 3.9 micro-releases enter double digits! There’s been 130 commits since 3.9.9 which is a higher number of fixes for this stage of the life cycle compared to 3.8. See the changelog for details on what changed.

The next Python 3.9 maintenance release will be 3.9.11, currently scheduled for Pi Day '22 (2022-03-14).

Python 3.11.0a4

Get it here: https://www.python.org/downloads/release/python-3110a4/

Python 3.11 is still in development. This release, 3.11.0a4, is the fourth of seven planned alpha releases.

Alpha releases are intended to make it easier to test the current state of new features and bug fixes by the community, as well as to test the release process.

During the alpha phase, features may be added up until the start of the beta phase (2022-05-06) and, if necessary, may be modified or deleted up until the release candidate phase (2022-08-01). Please keep in mind that this is a preview release and its use is not recommended for production environments.

Many new features for Python 3.11 are still being planned and written. Among the new major new features and changes so far:

PEP 657 – Include Fine-Grained Error Locations in Tracebacks
PEP 654 – Exception Groups and except*
The Faster CPython Project is already yielding some exciting results: this version of CPython 3.11 is ~ 19% faster on the geometric mean of the PyPerformance benchmarks, compared to 3.10.0.
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.11 will be 3.11.0a5, currently scheduled for Wednesday, 2022-02-02.

Python 3.6 is pining for the fjords

Python 3.6 is no more. It’s an ex-Python. It has ceased to be. On December 23rd 2021 is has reached its end-of-life phase after five successful years.

It’s been the first truly popular Python 3 release, introducing f-strings to the world and making big improvements to both asyncio (async generators!) and typing (variable annotations!).

We’d like to congratulate Ned Deily @nad on successfully driving the 3.6 series to completion as Release Manager. He’s not fully retired yet, as 3.7, which he is also managing, is still receiving security patches until June 2023.

We hope you enjoy the new releases

Your friendly release team,
Pablo Galindo Salgado @pablogsal
Łukasz Langa @ambv

Python 3.11.0a3 is available

2021-12-08T18:54:00.003-05:00

You can tell that we are slowly getting closer to the first beta as the number of release blockers that we need to fix on every release starts to increase But we did it!

https://www.python.org/downloads/release/python-3110a1/

Major new features of the 3.11 series, compared to 3.10

Among the new major new features and changes so far:

PEP 657 – Include Fine-Grained Error Locations in Tracebacks
PEP 654 – PEP 654 – Exception Groups and except*
The Faster Cpython Project is already yielding some exciting results: this version of CPython 3.11 is ~19% faster on the geometric mean of the performance benchmarks, compared to 3.10.0.

(Hey,

fellow core developer,

if a feature you find important is missing from this list,

let Pablo know

The next pre-release of Python 3.11 will be 3.11.0a3, currently scheduled for 2022-01-03.

More resources

Online Documentation

PEP 664, 3.11 Release Schedule
Report bugs at https://bugs.python.org.

Help fund Python and its community.

And now for something completely different

Rayleigh scattering, named after the nineteenth-century British physicist Lord Rayleigh is the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation. For light frequencies well below the resonance frequency of the scattering particle, the amount of scattering is inversely proportional to the fourth power of the wavelength. Rayleigh scattering results from the electric polarizability of the particles. The oscillating electric field of a light wave acts on the charges within a particle, causing them to move at the same frequency. The particle, therefore, becomes a small radiating dipole whose radiation we see as scattered light. The particles may be individual atoms or molecules; it can occur when light travels through transparent solids and liquids but is most prominently seen in gases.

The strong wavelength dependence of the scattering means that shorter (blue) wavelengths are scattered more strongly than longer (red) wavelengths. This results in the indirect blue light coming from all regions of the sky.

We hope you enjoy the new releases!

https://www.python.org/psf/

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal

Python 3.10.1 is available

2021-12-06T19:07:00.003-05:00

I hope you like bug fixes, because we have a whole shipment of them! Python 3.10.1 is the first maintenance release of Python 3.10 as we have packed more than 330 commits of fixes and general improvements. You can get it here:

https://www.python.org/downloads/release/python-3101/

This is the first maintenance release of Python 3.10

Python 3.10.1 is the newest major release of the Python programming language, and it contains many new features and optimizations.

Major new features of the 3.10 series, compared to 3.9

Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.

PEP 604 – Allow writing union types as X | Y

PEP 612 – Parameter Specification Variables

PEP 626 – Precise line numbers for debugging and other tools.

PEP 618 – Add Optional Length-Checking To zip.

bpo-12782: Parenthesized context managers are now officially allowed.

PEP 632 – Deprecate distutils module.

PEP 613 – Explicit Type Aliases

PEP 634 – Structural Pattern Matching: Specification

PEP 635 – Structural Pattern Matching: Motivation and Rationale

PEP 636 – Structural Pattern Matching: Tutorial

PEP 644 – Require OpenSSL 1.1.1 or newer

PEP 624 – Remove Py_UNICODE encoder APIs

PEP 597 – Add optional EncodingWarning

More resources

Online Documentation

PEP 619, 3.10 Release Schedule

Report bugs at https://bugs.python.org.

Help fund Python and its community.

bpo-38605: from __future__ import annotations (PEP 563) used to be on this list in previous pre-releases but it has been postponed to Python 3.11 due to some compatibility concerns. You can read the Steering Council communication about it here to learn more.

And now for something completely different

The Meissner effect (or Meissner–Ochsenfeld effect) is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state when it is cooled below the critical temperature. This expulsion will repel a nearby magnet. The German physicists Walther Meissner and Robert Ochsenfeld discovered this phenomenon in 1933 by measuring the magnetic field distribution outside superconducting tin and lead samples. The experiment demonstrated for the first time that superconductors were more than just perfect conductors and provided a uniquely defining property of the superconductor state. The ability for the expulsion effect is determined by the nature of equilibrium formed by the neutralization within the unit cell of a superconductor.

You can do very cool things with it!

We hope you enjoy the new releases!

https://www.python.org/psf/

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal

Python 3.9.9 hotfix release is now available

2021-11-15T17:09:00.004-05:00

Get it here: https://www.python.org/downloads/release/python-399/

Python 3.9.9 is the eighth maintenance release of the legacy 3.9 series. Python 3.10 is now the latest feature release series of Python 3. Get the latest release of 3.10.x here.

3.9.9 was released out of schedule as a hotfix for an argparse regression in Python 3.9.8 which caused complex command-line tools to fail recognizing sub-commands properly. Details in BPO-45235. There are only three other bugfixes in this release compared to 3.9.8. See the changelog for details on what changed.

Upgrading to 3.9.9 is highly recommended if you’re running Python 3.9.8.

The next Python 3.9 maintenance release will be 3.9.10, currently scheduled for 2022-01-03.

We apologize for the inconvenience

…and still hope you’ll enjoy the new release!

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Łukasz Langa @ambv

Python 3.9.8 and 3.11.0a2 are now available

2021-11-05T19:09:00.000-04:00

Tcl/Tk updates

With the recent release of macOS 12 Monterey, we noticed that tkinter file dialogs are failing to show up on this new operating system, including in our built-in IDLE. Thanks to rapid help from the Tk team, and Marc Culler in particular, we were able to fix the issue by bundling Python 3.9.8 and Python 3.11.0a2 with a fixed Tcl/Tk version. In 3.9.8 it’s a patched 8.6.11 release while 3.11.0a2 is rocking the bleeding-edge 8.6.12rc1.

Since the issue also affected our latest stable version, 3.10.0, an updated macOS installer for this version was issued. You can recognize it by the post2 version appendix: python-3.10.0post2-macos11.pkg. We didn’t have to bump the version number of Python itself since there are no Python source differences between this package and the original 3.10.0. The only difference is the bundled patched Tcl/Tk library.

Initially the original 3.10.0 installer was removed from the website after all URLs got updated to point to the patched version but it turned out this breaks some workflows so the patched installer is now also available under the original filename.

Python 3.9.8

Get it here: https://www.python.org/downloads/release/python-398/

Python 3.9.8 is the seventh maintenance release of the legacy 3.9 series. Python 3.10 is now the latest feature release series of Python 3. Get the latest release of 3.10.x here.

There’s been 202 commits since 3.9.7 which shows that there’s still considerable interest in improving Python 3.9. To compare, at the same stage of the release cycle Python 3.8 received over 25% fewer commits. See the changelog for details on what changed.

On macOS, the default installer is now the new universal2 variant. It’s compatible with Mac OS X 10.9 and newer, including macOS 11 Big Sur and macOS 12 Monterey. You may need to upgrade third-party components, like pip, to the newest versions. You may experience differences in behavior in IDLE and other Tk-based applications due to using the newest version of Tk. As always, if you encounter problems when using this installer variant, please check https://bugs.python.org for existing reports and for opening new issues.

The next Python 3.9 maintenance release will be 3.9.9, currently scheduled for 2022-01-03.

Python 3.11.0a2

Python 3.11 is still in development. This release, 3.11.0a2 is the second of seven planned alpha releases.

Alpha releases are intended to make it easier to test the current state of new features and bug fixes and to test the release process.

Many new features for Python 3.11 are still being planned and written. Among the new major new features and changes so far:

PEP 657 – Include Fine-Grained Error Locations in Tracebacks
The Faster CPython Project 1 is already yielding some exciting results: this version of CPython 3.11 is ~12% faster on the geometric mean of the PyPerformance benchmarks, compared to 3.10.0.
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.11 will be 3.11.0a3, currently scheduled for Monday, 2021-12-06.

We hope you enjoy the new releases

Your friendly release team,
Ned Deily @nad
Pablo Galindo Salgado @pablogsal
Steve Dower @steve.dower
Łukasz Langa @ambv

Python 3.11.0a1 is available

2021-10-07T08:03:00.006-04:00

Now that we are on a release spree, here you have the first alpha release of Python 3.11: Python 3.11.0a1. Let the testing and validation games begin!

https://www.python.org/downloads/release/python-3110a1/

Major new features of the 3.11 series, compared to 3.10

Among the new major new features and changes so far:

PEP 657 – Include Fine-Grained Error Locations in Tracebacks
PEP 654 – PEP 654 – Exception Groups and except*
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.11 will be 3.11.0a2, currently scheduled for 2021-11-02.

More resources

Online Documentation

PEP 664, 3.11 Release Schedule
Report bugs at https://bugs.python.org.

Help fund Python and its community.

And now for something completely different

Schwarzschild black holes are also unique because they have a space-like singularity at their core, which means that the singularity doesn't happen at a specific point in *space* but happens at a specific point in *time* (the future). This means once you are inside the event horizon you cannot point with your finger towards the direction the singularity is located because the singularity happens in your future: no matter where you move, you will "fall" into it.

For a Schwarzschild black hole (a black hole with no rotation or electromagnetic charge), given a free fall particle starting at the event horizon, the maximum propper time (which happens when it falls without angular velocity) it will experience to fall into the singularity is `π*M` (in natural units), where M is the mass of the black hole. For Sagittarius A* (the black hole at the centre of the milky way) this time is approximately 1 minute.

We hope you enjoy the new releases!

https://www.python.org/psf/

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal

Python 3.10.0 is available

2021-10-04T17:07:00.006-04:00

On behalf of the Python development community and the Python 3.10 release team, I’m pleased to announce the availability of Python 3.10.0.

Python 3.10.0 is the newest major release of the Python programming language, and it contains many new features and optimizations.

https://www.python.org/downloads/release/python-3100/

Major new features of the 3.10 series, compared to 3.9

Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.

PEP 604 – Allow writing union types as X | Y

PEP 612 – Parameter Specification Variables

PEP 626 – Precise line numbers for debugging and other tools.

PEP 618 – Add Optional Length-Checking To zip.

bpo-12782: Parenthesized context managers are now officially allowed.

PEP 632 – Deprecate distutils module.

PEP 613 – Explicit Type Aliases

PEP 634 – Structural Pattern Matching: Specification

PEP 635 – Structural Pattern Matching: Motivation and Rationale

PEP 636 – Structural Pattern Matching: Tutorial

PEP 644 – Require OpenSSL 1.1.1 or newer

PEP 624 – Remove Py_UNICODE encoder APIs

PEP 597 – Add optional EncodingWarning

More resources

Online Documentation

PEP 619, 3.10 Release Schedule

Report bugs at https://bugs.python.org.

Help fund Python and its community.

And now for something completely different

We hope you enjoy the new releases!

https://www.python.org/psf/

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal

Python 3.10.0rc2 is available

2021-09-07T19:33:00.004-04:00

Python 3.10 is one month away, can you believe it? This snake is still trying to bite as it has been an interesting day of fighting fires, release blockers, and a bunch of late bugs but your friendly release team always delivers

You can get this new release while is still fresh here:

https://www.python.org/downloads/release/python-3100rc2/

This release, 3.10.0rc2, is the last preview before the final release of Python 3.10.0 on 2021-10-04. Entering the release candidate phase, only reviewed code changes which are clear bug fixes are allowed between release candidates and the final release. There will be no ABI changes from this point forward in the 3.10 series and the goal is that there will be as few code changes as possible.

Call to action

The 3.10 branch is now accepting changes for 3.10.1. To maximize stability, the final release will be cut from the v3.10.0rc2 tag. If you need the release manager to cherry-pick any critical fixes, mark issues as release blockers and/or add him as a reviewer on a critical backport PR on GitHub.

To see which changes are currently cherry-picked for inclusion in 3.10.0, look at the short-lived branch-v3.10.0 https://github.com/python/cpython/tree/branch-v3.10.0 on GitHub.

Core developers: all eyes on the docs now

Are all your changes properly documented?

Did you notice other changes you know of to have insufficient documentation?

Community members

We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.10 compatibilities during this phase. As always, report any issues to the Python bug tracker.

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

Major new features of the 3.10 series, compared to 3.9

Many new features for Python 3.10 are still being planned and written. Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.
PEP 604 – Allow writing union types as X | Y
PEP 612 – Parameter Specification Variables
PEP 626 – Precise line numbers for debugging and other tools.
PEP 618 – Add Optional Length-Checking To zip.
bpo-12782: Parenthesized context managers are now officially allowed.
PEP 632 – Deprecate distutils module.
PEP 613 – Explicit Type Aliases
PEP 634 – Structural Pattern Matching: Specification
PEP 635 – Structural Pattern Matching: Motivation and Rationale
PEP 636 – Structural Pattern Matching: Tutorial
PEP 644 – Require OpenSSL 1.1.1 or newer
PEP 624 – Remove Py_UNICODE encoder APIs
PEP 597 – Add optional EncodingWarning
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next release will be the final release of Python 3.10.0, which is currently scheduled for Monday, 2021-10-04.

More resources

And now for something completely different

Maxwell’s demon is a thought experiment that would hypothetically violate the second law of thermodynamics. It was proposed by the physicist James Clerk Maxwell in 1867. In the thought experiment, a demon controls a small massless door between two chambers of gas. As individual gas molecules (or atoms) approach the door, the demon quickly opens and closes the door to allow only fast-moving molecules to pass through in one direction, and only slow-moving molecules to pass through in the other. Because the kinetic temperature of a gas depends on the velocities of its constituent molecules, the demon’s actions cause one chamber to warm up and the other to cool down. This would decrease the total entropy of the two gases, without applying any work, thereby violating the second law of thermodynamics.

We hope you enjoy those new releases!

Your friendly release team,

Pablo Galindo @pablogsal

Ned Deily @nad

Steve Dower @steve.dower

Python 3.7.12 and 3.6.15 security updates now available

2021-09-04T18:00:00.001-04:00

Python 3.7.12 and 3.6.15, the lastest security fix rollups for Python 3.7 and Python 3.6, are now available. You can find the release files, links to the changelogs, and more information here:

https://www.python.org/downloads/release/python-3712/
https://www.python.org/downloads/release/python-3615/

These releases are source code only; Windows and macOS binary installers are not provided for security fix releases.

Note that Python 3.9 is now the latest feature release series of Python 3. You should consider upgrading to 3.9 as soon as practical. Get the latest release of 3.9.x here.

Python 3.9.7 and 3.8.12 are now available

2021-08-30T18:32:00.000-04:00

Python 3.9.7

Python 3.9.7 is the newest major stable release of the Python programming language, and it contains many new features and optimizations. There’s been 187 commits since 3.9.6 which is a similar amount compared to 3.8 at the same stage of the release cycle. See the change log for details.

On macOS, we encourage you to use the universal2 binary installer variant whenever possible. The legacy 10.9+ Intel-only variant will not be provided for Python 3.10 and the universal2 variant will become the default download for 3.9.8. You may need to upgrade third-party components, like pip, to later versions. You may experience differences in behavior in IDLE and other Tk-based applications due to using the newer version of Tk. As always, if you encounter problems when using this installer variant, please check https://bugs.python.org for existing reports and for opening new issues.

The next Python 3.9 maintenance release will be 3.9.8, currently scheduled for 2021-11-01.

The Second Security-Only Release of Python 3.8

Security content in this release contains four fixes. There are also four additional fixes for bugs that might have lead to denial-of-service attacks. Finally, while we’re not providing binary installers anymore, for those users who produce installers, we upgraded the OpenSSL version used to 1.1.1l. Take a look at the change log for details.

According to the release calendar specified in PEP 569, Python 3.8 is now in “security fixes only” stage of its life cycle: 3.8 branch only accepts security fixes and releases of those are made irregularly in source-only form until October 2024. Python 3.8 isn’t receiving regular bug fixes anymore, and binary installers are no longer provided for it. Python 3.8.10 was the last full bugfix release of Python 3.8 with binary installers.

Security releases of 3.7.12 and 3.6.15

Those aren’t ready just yet but are soon to follow.

Similarly to 3.8, Python 3.7 and 3.6 are now in “security fixes only” stage of their life cycle. Python 3.7 will be providing source archives until June 2023 while Python 3.6 ends its life in December 2021.

We hope you enjoy the new releases

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Łukasz Langa @ambv

Python 3.10.0rc1 is available

2021-08-03T12:34:00.002-04:00

Python 3.10.0 is almost ready. This release, 3.10.0rc1, is the penultimate release preview. You can get it here:

https://www.python.org/downloads/release/python-3100rc1/

This release, **3.10.0rc1**, 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

currently planned for 2021-09-06 while the official release is planned for 2021-10-04.

There will be no ABI changes from this point forward in the 3.10 series and the goal is that there will be as few code changes as possible.

Call to action

Core developers: all eyes on the docs now

Are all your changes properly documented?
Did you notice other changes you know of to have insufficient documentation?

Community members

We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.10 compatibilities during this phase. As always, report any issues to the Python bug tracker.

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

Major new features of the 3.10 series, compared to 3.9

Many new features for Python 3.10 are still being planned and written. Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.
PEP 604 – Allow writing union types as X | Y
PEP 612 – Parameter Specification Variables
PEP 626 – Precise line numbers for debugging and other tools.
PEP 618 – Add Optional Length-Checking To zip.
bpo-12782: Parenthesized context managers are now officially allowed.
PEP 632 – Deprecate distutils module.
PEP 613 – Explicit Type Aliases
PEP 634 – Structural Pattern Matching: Specification
PEP 635 – Structural Pattern Matching: Motivation and Rationale
PEP 636 – Structural Pattern Matching: Tutorial
PEP 644 – Require OpenSSL 1.1.1 or newer
PEP 624 – Remove Py_UNICODE encoder APIs
PEP 597 – Add optional EncodingWarning
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release, the second release candidate, will only be released if needed (scheduled for Monday, 2021-09-06). Otherwise, the next release will directly be the final release of Python 3.10.0, which is currently scheduled for Monday, 2021-10-04.

More resources

And now for something completely different

In quantum physics, the spin is an intrinsic form of angular momentum carried by elementary particles, composite particles, and atomic nuclei. The spin is one of two types of angular momentum in quantum mechanics, the other being orbital angular momentum. The orbital angular momentum operator is the quantum-mechanical counterpart to the classical angular momentum of orbital revolution and appears when there is periodic structure to its wavefunction as the angle varies. For photons, spin is the quantum-mechanical counterpart of the polarization of light; for electrons, the spin has no classical counterpart.

We hope you enjoy those new releases!

Your friendly release team,

Pablo Galindo @pablogsal

Ned Deily @nad

Steve Dower @steve.dower

Python 3.10.0b4 is available

2021-07-10T21:48:00.005-04:00

Wow! A release on a Saturday? Do the release management team even rest? You better believe it, because this is the last of the planned beta releases. This means that the next pre-release will be the first release candidate of Python 3.10.0. Remember that our goal is to have no ABI changes after this beta and a few code changes as possible after 3.10.0rc1.

The final release is closer and closer.... just a few more months!

https://www.python.org/downloads/release/python-3100b4/

This is a beta preview of Python 3.10

Python 3.10 is still in development. 3.10.0b4 is the fourth and last of the beta release previews. 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 3.10** during the beta phase and report issues found to [the Python bug tracker](https://bugs.python.org/) 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 (Monday, 2021-08-02). Our goal is to have no ABI changes after beta 4 and as few code changes as possible after 3.10.0rc1, the first release candidate. To achieve that, it will be **extremely important** to get as much exposure for 3.10 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 3.10 series, compared to 3.9

Many new features for Python 3.10 are still being planned and written. Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.
PEP 604 – Allow writing union types as X | Y
PEP 612 – Parameter Specification Variables
PEP 626 – Precise line numbers for debugging and other tools.
PEP 618 – Add Optional Length-Checking To zip.
bpo-12782: Parenthesized context managers are now officially allowed.
PEP 632 – Deprecate distutils module.
PEP 613 – Explicit Type Aliases
PEP 634 – Structural Pattern Matching: Specification
PEP 635 – Structural Pattern Matching: Motivation and Rationale
PEP 636 – Structural Pattern Matching: Tutorial
PEP 644 – Require OpenSSL 1.1.1 or newer
PEP 624 – Remove Py_UNICODE encoder APIs
PEP 597 – Add optional EncodingWarning
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release, the first release candidate of Python 3.10.0, will be 3.10.0rc1. It is currently scheduled for Monday, 2021-08-02.

More resources

And now for something completely different

We hope you enjoy those new releases!

Your friendly release team,

Pablo Galindo @pablogsal

Ned Deily @nad

Steve Dower @steve.dower

Python 3.9.6, 3.8.11, 3.7.11, and 3.6.14 are now available

2021-06-28T15:10:00.001-04:00

Python 3.9.6

Get it here: https://www.python.org/downloads/release/python-396/

Python 3.9.6 is the newest major stable release of the Python programming language, and it contains many new features and optimizations. There’s been 146 commits since 3.9.5 which is a similar amount compared to 3.8 at the same stage of the release cycle. See the change log for details.

On macOS, we encourage you to use the universal2 binary installer variant whenever possible. The legacy 10.9+ Intel-only variant will not be provided for Python 3.10 and the universal2 variant will become the default download for future 3.9.x releases. You may need to upgrade third-party components, like pip, to later versions once they are released. You may experience differences in behavior in IDLE and other Tk-based applications due to using the newer version of Tk. As always, if you encounter problems when using this installer variant, please check https://bugs.python.org for existing reports and for opening new issues.

The next Python 3.9 maintenance release will be 3.9.7, currently scheduled for 2021-08-30.

The First Security-Only Release of Python 3.8

Get it here: https://www.python.org/downloads/release/python-3811/

Security content in this release contains three fixes. There’s also two fixes for 3.8.10 regressions. Take a look at the change log for details.

According to the release calendar specified in PEP 569, Python 3.8 is now in security fixes only stage of its life cycle: 3.8 branch only accepts security fixes and releases of those are made irregularly in source-only form until October 2024. Python 3.8 isn’t receiving regular bugfixes anymore, and binary installers are no longer provided for it. Python 3.8.10 was the last full bugfix release of Python 3.8 with binary installers.

Security releases of 3.7.11 and 3.6.14

Get them here:
https://www.python.org/downloads/release/python-3711/
https://www.python.org/downloads/release/python-3614/

Security content in those releases contains five fixes each. Check out the relevant change logs for 3.7.11 and 3.6.14 for details.

Similarly to 3.8, Python 3.7 and 3.6 are now in security fixes only stage of their life cycle. Python 3.7 will be providing them until June 2023 while Python 3.6 ends its life in December 2021.

We hope you enjoy the new releases

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Łukasz Langa @ambv

Python 3.10.0b3 is available

2021-06-17T17:38:00.000-04:00

Summer is almost here (at least in half of the planet) and Python 3.10 is finishing baking in the oven. For those of you that want to taste it before is finally ready (and if you are a library developer, you certainly do!) you can have the second-to-last beta now, but be careful as is very hot

https://www.python.org/downloads/release/python-3100b3/

This is a beta preview of Python 3.10

Python 3.10 is still in development. 3.10.0b3 is the third of four planned beta release previews. 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.

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

Major new features of the 3.10 series, compared to 3.9

Many new features for Python 3.10 are still being planned and written. Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.
PEP 604 – Allow writing union types as X | Y
PEP 612 – Parameter Specification Variables
PEP 626 – Precise line numbers for debugging and other tools.
PEP 618 – Add Optional Length-Checking To zip.
bpo-12782: Parenthesized context managers are now officially allowed.
PEP 632 – Deprecate distutils module.
PEP 613 – Explicit Type Aliases
PEP 634 – Structural Pattern Matching: Specification
PEP 635 – Structural Pattern Matching: Motivation and Rationale
PEP 636 – Structural Pattern Matching: Tutorial
PEP 644 – Require OpenSSL 1.1.1 or newer
PEP 624 – Remove Py_UNICODE encoder APIs
PEP 597 – Add optional EncodingWarning
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.10 will be 3.10.0b4, currently scheduled for Saturday, 2021-07-10.

More resources

And now for something completely different

There are no green stars. Why? In general, objects don't emit a single wavelength of light when they shine. Instead, they emit photons in a range of wavelengths. If you were to use some sort of detector that is sensitive to the wavelengths of light emitted by an object, and then plotted the number of them versus wavelength, you get a lopsided plot called a blackbody curve. For an object as hot as the Sun, that curve peaks at blue-green, so it emits most of its photons there. But it still emits some that are bluer, and some that are redder. When we look at the Sun, we see all these colors blended together. Our eyes mix them up to produce one color: white. A warmer star will put out more blue, and a cooler one redder, but no matter what, our eyes just won't see that as green. Due to how we perceive color, the only way to see a star as being green is for it to be only emitting green light. But as starts always emit radiation following the blackbody curve, that's pretty much impossible.

We hope you enjoy those new releases!

Your friendly release team,

Pablo Galindo @pablogsal

Ned Deily @nad

Steve Dower @steve.dower

Python 3.10.0b2 is available

2021-06-01T07:04:00.002-04:00

After fighting with some release blockers, implementing a bunch of GC traversal functions, and fixing some pending reference leaks, we finally have Python 3.10.0 beta 2 ready for you! Thanks to everyone that helped to unblock the release!

https://www.python.org/downloads/release/python-3100b2/

This is a beta preview of Python 3.10

Python 3.10 is still in development. 3.10.0b2 is the second of four planned beta release previews. 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.

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

Major new features of the 3.10 series, compared to 3.9

Many new features for Python 3.10 are still being planned and written. Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.
PEP 604 – Allow writing union types as X | Y
PEP 612 – Parameter Specification Variables
PEP 626 – Precise line numbers for debugging and other tools.
PEP 618 – Add Optional Length-Checking To zip.
bpo-12782: Parenthesized context managers are now officially allowed.
PEP 632 – Deprecate distutils module.
PEP 613 – Explicit Type Aliases
PEP 634 – Structural Pattern Matching: Specification
PEP 635 – Structural Pattern Matching: Motivation and Rationale
PEP 636 – Structural Pattern Matching: Tutorial
PEP 644 – Require OpenSSL 1.1.1 or newer
PEP 624 – Remove Py_UNICODE encoder APIs
PEP 597 – Add optional EncodingWarning
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.10 will be 3.10.0b3, currently scheduled for Thursday, 2021-06-17.

More resources

And now for something completely different

The Ehrenfest paradox concerns the rotation of a "rigid" disc in the theory of relativity. In its original 1909 formulation as presented by Paul Ehrenfest in relation to the concept of Born rigidity within special relativity, it discusses an ideally rigid cylinder that is made to rotate about its axis of symmetry. The radius R as seen in the laboratory frame is always perpendicular to its motion and should therefore be equal to its value R0 when stationary. However, the circumference (2πR) should appear Lorentz-contracted to a smaller value than at rest. This leads to the apparent contradiction that R = R0 and R < R0.

We hope you enjoy those new releases!

Your friendly release team,

Pablo Galindo @pablogsal

Ned Deily @nad

Steve Dower @steve.dower

Python 3.8.10, 3.9.5, and 3.10.0b1 are now available

2021-05-03T19:16:00.002-04:00

This has been a very busy day for releases and on behalf of the Python development community we’re happy to announce the availability of three new Python releases.

Python 3.10 is now in Beta

Get it here: https://www.python.org/downloads/release/python-3100b1/

Python 3.10 is still in development. 3.10.0b1 is the first of four planned beta release previews. 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 3.10 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 (Monday, 2021-08-02). Our goal is have no ABI changes after beta 4 and as few code changes as possible after 3.10.0rc1, the first release candidate. To achieve that, it will be extremely important to get as much exposure for 3.10 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.

The next pre-release, the second beta release of Python 3.10, will be 3.10.0b2. It is currently scheduled for 2021-05-25. Please see PEP 619 for details.

Development Begins on Python 3.11

With Python 3.10 moving to beta, it received its own 3.10 branch in the repository. All new features are now targeting Python 3.11, to be released in October 2022.

Using the opportunity with the creation of the 3.10 branch, we renamed the master branch of the repository to main. It’s been a bit rocky but looks like we’re open for business. Please rename the main branch of your personal fork using the guide GitHub will give you when you go to your fork’s main page. In case of any outstanding issues, please contact the 3.11 RM.

Python 3.9.5

Get it here: https://www.python.org/downloads/release/python-395/

Python 3.9.5 is the newest major stable release of the Python programming language, and it contains many new features and optimizations. There’s been 111 commits since 3.9.4 which is a similar amount compared to 3.8 at the same stage of the release cycle. See the change log for details.

On macOS, we encourage you to use the universal2 binary installer variant whenever possible. The legacy 10.9+ Intel-only variant will not be provided for Python 3.10 and the universal2 variant will become the default download for future 3.9.x releases. You may need to upgrade third-party components, like pip, to later versions once they are released. You may experience differences in behavior in IDLE and other Tk-based applications due to using the newer version of Tk. As always, if you encounter problems when using this installer variant, please check https://bugs.python.org for existing reports and for opening new issues.

The next Python 3.9 maintenance release will be 3.9.6, currently scheduled for 2021-06-28.

The Last Regular Bugfix Release of Python 3.8

Get it here: https://www.python.org/downloads/release/python-3810/

According to the release calendar specified in PEP 569, Python 3.8.10 is the final regular maintenance release. Starting now, the 3.8 branch will only accept security fixes and releases of those will be made in source-only form until October 2024. To keep receiving regular bug fixes, please upgrade to Python 3.9.

Compared to the 3.7 series, this last regular bugfix release is relatively dormant at 92 commits since 3.8.9. Version 3.7.8, the final regular bugfix release of Python 3.7, included 187 commits. But there’s a bunch of important updates here regardless, the biggest being macOS Big Sur and Apple Silicon build support. This work would not have been possible without the effort of Ronald Oussoren, Ned Deily, Maxime Bélanger, and Lawrence D’Anna from Apple. Thank you!

Take a look at the change log for details.

We hope you enjoy the new releases

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Pablo Galindo Salgado @pablogsal
Łukasz Langa @ambv

Python 3.10.0a7 is now available for testing

2021-04-06T07:30:00.006-04:00

Brrrrr… do you feel that? That’s the chill of beta freeze coming closer. Meanwhile, your friendly CPython release team doesn’t rest even on holidays and we have prepared a shiny new release for you: Python 3.10.0a7.

Get the new release here:

https://www.python.org/downloads/release/python-3100a7/

Python 3.10.0a7

Release Date: April 5, 2021

This is an early developer preview of Python 3.10

Major new features of the 3.10 series, compared to 3.9

Python 3.10 is still in development. This release, 3.10.0a7 is the last of seven planned alpha releases. Alpha releases are intended to make it easier to test the current state of new features and bug fixes and to test the release process. During the alpha phase, features may be added up until the start of the beta phase (2021-05-03) and, if necessary, may be modified or deleted up until the release candidate phase (2021-10-04). Please keep in mind that this is a preview release and its use is not recommended for production environments.

Many new features for Python 3.10 are still being planned and written. Among the new major new features and changes so far:

PEP 623 – Deprecate and prepare for the removal of the wstr member in PyUnicodeObject.
PEP 604 – Allow writing union types as X | Y
PEP 612 – Parameter Specification Variables
PEP 626 – Precise line numbers for debugging and other tools.
bpo-38605: from __future__ import annotations (PEP 563) is now the default.
PEP 618 – Add Optional Length-Checking To zip.
bpo-12782: Parenthesized context managers are now officially allowed.
PEP 632 – Deprecate distutils module.
PEP 613 – Explicit Type Aliases
PEP 634 – Structural Pattern Matching: Specification
PEP 635 – Structural Pattern Matching: Motivation and Rationale
PEP 636 – Structural Pattern Matching: Tutorial
PEP 644 – Require OpenSSL 1.1.1 or newer
PEP 624 – Remove Py_UNICODE encoder APIs
PEP 597 – Add optional EncodingWarning
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.10 will be 3.10.0b1 ( the first beta release and feature freeze ), currently scheduled for Monday, 2021-05-03.

More resources

And now for something completely different

In physics, the twin paradox is a thought experiment in special relativity involving identical twins, one of whom makes a journey into space in a high-speed rocket and returns home to find that the twin who remained on Earth has aged more. This result appears puzzling because each twin sees the other twin as moving, and so, as a consequence of an incorrect and naive application of time dilation and the principle of relativity, each should paradoxically find the other to have aged less. However, this scenario can be resolved by realising that the travelling twin is undergoing acceleration, which makes him a non-inertial observer. In both views, there is no symmetry between the spacetime paths of the twins. Therefore, the twin paradox is not a paradox in the sense of a logical contradiction.

We hope you enjoy those new releases!

Your friendly release team,
Pablo Galindo Salgado @pablogsal
Ned Deily @nad
Steve Dower @steve.dower

Python 3.9.4 hotfix is now available

2021-04-04T15:19:00.000-04:00

Python 3.9.3 was released two days ago on Friday, April 2nd. It contains important security content listed below for reference. Unfortunately, it also introduced an unintentional ABI incompatibility, making some C extensions built with Python 3.9.0 - 3.9.2 crash with Python 3.9.3 on 32-bit systems. To minimize disruption, I decided to recall 3.9.3 and introduce this hotfix release: 3.9.4.

We highly recommend upgrading your Python 3.9 installations to 3.9.4 at your earliest convenience.

Get it here:

https://www.python.org/downloads/release/python-394/

What is “ABI compatibility”?

Python guarantees that within a given language series (like the current 3.9) binary extensions written in C or C++ and compiled against headers of one release (like 3.9.0) will be importable from other versions in the same series (like 3.9.3). If this weren’t the case, library authors would have to ship separate binary wheels on PyPI for every single bugfix release of Python. That would be very inconvenient.

What broke in Python 3.9.3?

In a fix for a corner-case crash around recursion limits and exceptions, the PyThreadState struct needed to change. While PyThreadState’s only documented public member is the *interp field, it’s not uncommon for C extensions to access other fields in this struct as well.

When I approved the backport of this fix, I missed the fact that the variable size change would change the memory layout of said struct on 32-bit systems (on 64-bit systems alignment rules made the size change backwards compatible). Merging the backport was a mistake, and so 3.9.4 reverts it to restore compatibility with binary extensions built against Python 3.9.0 - 3.9.2. Details in bpo-43710.

Security Content in Python 3.9.3

bpo-43631: high-severity CVE-2021-3449 and CVE-2021-3450 were published for OpenSSL, it’s been upgraded to 1.1.1k in CI, and macOS and Windows installers.
bpo-42988: CVE-2021-3426: Remove the getfile feature of the pydoc module which could be abused to read arbitrary files on the disk (directory traversal vulnerability). Moreover, even source code of Python modules can contain sensitive data like passwords. Vulnerability reported by David Schwörer.
bpo-43285: ftplib no longer trusts the IP address value returned from the server in response to the PASV command by default. This prevents a malicious FTP server from using the response to probe IPv4 address and port combinations on the client network. Code that requires the former vulnerable behavior may set a trust_server_pasv_ipv4_address attribute on their ftplib.FTP instances to True to re-enable it.
bpo-43439: Add audit hooks for gc.get_objects(), gc.get_referrers() and gc.get_referents(). Patch by Pablo Galindo.

Release Calendar

Maintenance releases for the 3.9 series will continue at regular bi-monthly intervals, with 3.9.5 planned for May 3rd 2021 as well.

What’s new?

The Python 3.9 series contains many new features and optimizations over 3.8. See the “What’s New in Python 3.9 ” document for more information about features included in the 3.9 series. We also have a detailed change log for 3.9.3 specifically.

Detailed information about all changes made in version 3.8.9 can be found in its respective changelog.

We hope you enjoy those new releases!

Your friendly release team,
Łukasz Langa @ambv
Ned Deily @nad
Steve Dower @steve.dower

Python 3.9.3 and 3.8.9 are now available

2021-04-02T13:55:00.009-04:00

Those are expedited security releases, recommended to all users. Get them here:

https://www.python.org/downloads/release/python-389/

Note: 3.9.3 has been recalled due to introducing unintentional ABI incompatibility. Download 3.9.4 instead: https://www.python.org/downloads/release/python-394/.

Security Content

bpo-43631: high-severity CVE-2021-3449 and CVE-2021-3450 were published for OpenSSL, it’s been upgraded to 1.1.1k in CI, and macOS and Windows installers.
bpo-42988: CVE-2021-3426: Remove the getfile feature of the pydoc module which could be abused to read arbitrary files on the disk (directory traversal vulnerability). Moreover, even source code of Python modules can contain sensitive data like passwords. Vulnerability reported by David Schwörer.
bpo-43285: ftplib no longer trusts the IP address value returned from the server in response to the PASV command by default. This prevents a malicious FTP server from using the response to probe IPv4 address and port combinations on the client network. Code that requires the former vulnerable behavior may set a trust_server_pasv_ipv4_address attribute on their ftplib.FTP instances to True to re-enable it.
bpo-43439: Add audit hooks for gc.get_objects(), gc.get_referrers() and gc.get_referents(). Patch by Pablo Galindo.

Release Calendar

Due to the security fixes, those releases are made a month sooner than planned. I decided to keep the release calendar intact, meaning that the last full regular maintenance release of Python 3.8 is still planned for May 3rd 2021, after which it will shift to source releases only for security bug fixes only. Maintenance releases for the 3.9 series will continue at regular bi-monthly intervals, with 3.9.3 planned for May 3rd 2021 as well.

What’s new?

Detailed information about all changes made in version 3.8.9 can be found in its respective changelog.

We hope you enjoy those new releases!

Your friendly release team,
Ned Deily @nad
Steve Dower @steve.dower
Łukasz Langa @ambv

Python 3.10.0a6 is now available for testing

2021-03-01T15:08:00.001-05:00

Remember us? It’s your friendly CPython release team and we have something we think you may like: The new alpha release of Python 3.10 is here, now with 100% more pattern matching. If I were you, I would download it and start playing with it. Extra points if you report us any bugs you find along the way! Are you confused about all this pattern matching business? Fear not, this release also includes some fantastic documentation and some shiny new “What’s new” entries.

Check them here and tell us how we can improve it:

https://docs.python.org/3.10/whatsnew/3.10.html

https://docs.python.org/3.10/tutorial/controlflow.html#match-statements

Go get the new alpha here:

https://www.python.org/downloads/release/python-3100a6/

This is an early developer preview of Python 3.10

Major new features of the 3.10 series, compared to 3.9

Python 3.10 is still in development. This release, 3.10.0a6 is the sixth of seven planned alpha releases.
Alpha releases are intended to make it easier to test the current state of new features and bug fixes and to test the release process.
During the alpha phase, features may be added up until the start of the beta phase (2021-05-03) and, if necessary, may be modified or deleted up until the release candidate phase (2021-10-04). Please keep in mind that this is a preview release and its use is not recommended for production environments.

Many new features for Python 3.10 are still being planned and written. Among the new major
new features and changes so far:

PEP 623 – Remove wstr from Unicode
PEP 604 – Allow writing union types as X | Y
PEP 612 – Parameter Specification Variables
PEP 626 – Precise line numbers for debugging and other tools.
bpo-38605: from __future__ import annotations (PEP 563) is now the default.
PEP 618 – Add Optional Length-Checking To zip.
bpo-12782: Parenthesized context managers are now officially allowed.
PEP 632 – Deprecate distutils module.
PEP 613 – Explicit Type Aliases
PEP 634 – Structural Pattern Matching: Specification
PEP 635 – Structural Pattern Matching: Motivation and Rationale
PEP 636 – Structural Pattern Matching: Tutorial
(Hey, fellow core developer, if a feature you find important is missing from this list, let Pablo know.)

The next pre-release of Python 3.10 will be 3.10.0a7 ( last alpha release), currently scheduled for Monday, 2021-04-05.

More resources

And now for something completely different

Schwarzschild wormholes, also known as Einstein–Rosen bridges (named after Albert Einstein and Nathan Rosen), are connections between areas of space that can be modelled as vacuum solutions to the Einstein field equations, and that are now understood to be intrinsic parts of the maximally extended version of the Schwarzschild metric describing an eternal black hole with no charge and no rotation. Here, “maximally extended” refers to the idea that the spacetime should not have any “edges”: it should be possible to continue this path arbitrarily far into the particle’s future or past for any possible trajectory of a free-falling particle (following a geodesic in the spacetime).

Although Schwarzschild wormholes are not traversable in both directions, their existence inspired Kip Thorne to imagine traversable wormholes created by holding the “throat” of a Schwarzschild wormhole open with exotic matter (material that has negative mass/energy).