Release Date: May 3, 2021

This is a beta preview of Python 3.10

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.

Major new features of the 3.10 series, compared to 3.9

Python 3.10 is still in development. This release, 3.10.0b1 is the first of four beta releases. 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.

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 3.10.0b2, currently scheduled for Tuesday, 2021-05-25.

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.

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

When a spherical non-rotating body of a critical radius collapses under its own gravitation under general relativity, theory suggests it will collapse to a single point. This is not the case with a rotating black hole (a Kerr black hole). With a fluid rotating body, its distribution of mass is not spherical (it shows an equatorial bulge), and it has angular momentum. Since a point cannot support rotation or angular momentum in classical physics (general relativity being a classical theory), the minimal shape of the singularity that can support these properties is instead a ring with zero thickness but non-zero radius, and this is referred to as a ringularity or Kerr singularity.