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Python 3.9.0a4

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

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


Version Operating System Description MD5 Sum File Size GPG
Gzipped source tarball Source release b19c6fcc7ba2923c089721ab10eca989 23.1 MB SIG
XZ compressed source tarball Source release 88513446b6c0be34d00becd0e8b6a9a4 17.2 MB SIG
macOS 64-bit installer macOS for OS X 10.9 and later e01bbc2d80ddce3a8f0f70d75d50e6a6 27.9 MB SIG
Windows help file Windows 6cb344ba4785a81dd7b845adee8565b0 8.2 MB SIG
Windows x86 embeddable zip file Windows b1cddc35fd3dfd1668ae1a5a862bcf94 6.9 MB SIG
Windows x86 executable installer Windows b280939f64f5b2268858b03b351e5445 25.5 MB SIG
Windows x86 web-based installer Windows ce464014a7201c5e9e74d9fffbb7ed1e 1.3 MB SIG
Windows x86-64 embeddable zip file Windows for AMD64/EM64T/x64 8dc92037f04499087d99a1ffeae269f5 7.7 MB SIG
Windows x86-64 executable installer Windows for AMD64/EM64T/x64 8d93a6344593f95b1e0412e42f64cd12 26.5 MB SIG
Windows x86-64 web-based installer Windows for AMD64/EM64T/x64 cc69270bd9edc31090b1432ec45cfe89 1.3 MB SIG