Warning: Python 3.9.0 reached end-of-life on 2025-10-31. It is no longer supported and does not receive security updates. We recommend upgrading to the latest Python release.

Note: Python 3.9.0a4 has been superseded by Python 3.9.25.

Release date: Feb. 26, 2020

This is an early developer preview of Python 3.9

Python 3.9 is still in development. This release, 3.9.0a4 is the fourth of six 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 (2020-05-18) and, if necessary, may be modified or deleted up until the release candidate phase (2020-08-10). Please keep in mind that this is a preview release and its use is not recommended for production environments.

Major new features of the 3.9 series, compared to 3.8

Many new features for Python 3.9 are still being planned and written. Among the new major new features and changes so far:

• PEP 584, Union Operators in dict
• PEP 593, Flexible function and variable annotations
• PEP 602, Python adopts a stable annual release cadence
• BPO 38379, garbage collection does not block on resurrected objects;
• BPO 38692, os.pidfd_open added that allows process management without races and signals;

• A number of standard library modules (audioop, ast, grp, _hashlib, pwd, _posixsubprocess, random, select, struct, termios, zlib) are now using the stable ABI defined by PEP 384.

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

The next pre-release of Python 3.9 will be 3.9.0a5, currently scheduled for 2020-03-16.

More resources

• Online Documentation
• PEP 596, 3.9 Release Schedule
• Report bugs at https://bugs.python.org.
• Help fund Python and its community.

And now for something completely different

Woman: What do you want?
Burglar: I want to come in and steal a few things, madam.
Woman: Are you an encydopaedia salesman?
Burglar: No madam, I'm a burglar, I burgle people.
Woman: I think you're an encyclopaedia salesman.
Burglar: Oh I'm not, open the door, let me in please.
Woman: If I let you in you'll sell me encyclopaedias.
Burglar: I won't, madam. I just want to come in and ransack the flat. Honestly.

Full Changelog