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PyPy v7.3.8: release of python 2.7, 3.7, 3.8, and 3.9

PyPy v7.3.8: release of python 2.7, 3.7, 3.8, and 3.9-beta

The PyPy team is proud to release version 7.3.8 of PyPy. It has been only a few months since our last release, but we have some nice speedups and bugfixes we wish to share. The release includes four different interpreters:

  • PyPy2.7, which is an interpreter supporting the syntax and the features of Python 2.7 including the stdlib for CPython 2.7.18+ (the + is for backported security updates)

  • PyPy3.7, which is an interpreter supporting the syntax and the features of Python 3.7, including the stdlib for CPython 3.7.12. This will be the last release of PyPy3.7.

  • PyPy3.8, which is an interpreter supporting the syntax and the features of Python 3.8, including the stdlib for CPython 3.8.12. This is our third release of this interpreter, and we are removing the "beta" tag.

  • PyPy3.9, which is an interpreter supporting the syntax and the features of Python 3.9, including the stdlib for CPython 3.9.10. As this is our first release of this interpreter, we relate to this as "beta" quality. We welcome testing of this version, if you discover incompatibilities, please report them so we can gain confidence in the version.

The interpreters are based on much the same codebase, thus the multiple release. This is a micro release, all APIs are compatible with the other 7.3 releases. Highlights of the release, since the release of 7.3.7 in late October 2021, include:

  • PyPy3.9 uses an RPython version of the PEG parser which brought with it a cleanup of the lexer and parser in general

  • Fixed a regression in PyPy3.8 when JITting empty list comprehensions

  • Tweaked some issues around changing the file layout after packaging to make the on-disk layout of PyPy3.8 more compatible with CPython. This requires setuptools>=58.1.0

  • RPython now allows the target executable to have a . in its name, so PyPy3.9 will produce a pypy3.9-c and Changing the name of the shared object to be version-specific (it used to be will allow it to live alongside other versions.

  • Building PyPy3.9+ accepts a --platlibdir argument like CPython.

  • Improvement in ssl's use of CFFI buffers to speed up recv and recvinto

  • Update the packaged OpenSSL to 1.1.1m

We recommend updating. You can find links to download the v7.3.8 releases here:

We would like to thank our donors for the continued support of the PyPy project. If PyPy is not quite good enough for your needs, we are available for direct consulting work. If PyPy is helping you out, we would love to hear about it and encourage submissions to our blog via a pull request to

We would also like to thank our contributors and encourage new people to join the project. PyPy has many layers and we need help with all of them: PyPy and RPython documentation improvements, tweaking popular modules to run on PyPy, or general help with making RPython's JIT even better. Since the previous release, we have accepted contributions from 6 new contributors, thanks for pitching in, and welcome to the project!

If you are a python library maintainer and use C-extensions, please consider making a HPy / CFFI / cppyy version of your library that would be performant on PyPy. In any case both cibuildwheel and the multibuild system support building wheels for PyPy.

What is PyPy?

PyPy is a Python interpreter, a drop-in replacement for CPython 2.7, 3.7, 3.8 and 3.9. It's fast (PyPy and CPython 3.7.4 performance comparison) due to its integrated tracing JIT compiler.

We also welcome developers of other dynamic languages to see what RPython can do for them.

This PyPy release supports:

  • x86 machines on most common operating systems (Linux 32/64 bits, Mac OS X 64 bits, Windows 64 bits, OpenBSD, FreeBSD)

  • 64-bit ARM machines running Linux. A shoutout to Huawei for sponsoring the VM running the tests.

  • s390x running Linux

  • big- and little-endian variants of PPC64 running Linux,

PyPy support Windows 32-bit, PPC64 big- and little-endian, and ARM 32 bit, but does not release binaries. Please reach out to us if you wish to sponsor releases for those platforms.

Known Issues with PyPy3.9

  • There is still a known speed regression around **kwargs handling

  • We slightly modified the concurrent future's ProcessExcecutorPool to start all the worker processes when the first task is received (like on Python3.8) to avoid an apparent race condition when using fork and threads (issue 3650).

What else is new?

For more information about the 7.3.8 release, see the full changelog.

Please update, and continue to help us make PyPy better.

Cheers, The PyPy team