Protobuf 3.20.1 wheel built for but does not support Python 3.6

[cliffwoolley]

What version of protobuf and what language are you using?
Version: 3.20.1
Language: Python 3.6

What operating system (Linux, Windows, ...) and version?
Linux

What did you do?
pip install -v protobuf==3.20.1

What did you expect to see
https://pypi.org/project/protobuf/3.20.1/#files shows that Python 3.6 wheels exist, e.g. https://files.pythonhosted.org/packages/ad/ec/aff2fe72ab434f20b139277df186516a3ab12545b1382839666c7425ecb5/protobuf-3.20.1-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.whl , so it should be installable.

What did you see instead?
While wheels with -cp36- in the name exist and are published, their metadata shows requires-python: >=3.7, meaning that pip will confusingly refuse to install (or even list) them:

  Link requires a different Python (3.6.9 not in: '>=3.7'): https://files.pythonhosted.org/packages/ad/ec/aff2fe72ab434f20b139277df186516a3ab12545b1382839666c7425ecb5/protobuf-3.20.1-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.whl#sha256=097c5d8a9808302fb0da7e20edf0b8d4703274d140fd25c5edabddcde43e081f (from https://pypi.org/simple/protobuf/) (requires-python:>=3.7)
  Link requires a different Python (3.6.9 not in: '>=3.7'): https://files.pythonhosted.org/packages/ef/c8/2e7f7feaf804b7206e6cc8fa3f0f49834a78f7cb127813d2c45e42d5f7bf/protobuf-3.20.1-py2.py3-none-any.whl#sha256=adfc6cf69c7f8c50fd24c793964eef18f0ac321315439d94945820612849c388 (from https://pypi.org/simple/protobuf/) (requires-python:>=3.7)
  Link requires a different Python (3.6.9 not in: '>=3.7'): https://files.pythonhosted.org/packages/19/96/1283259c25bc48a6df98fa096f66fc568b40137b93806ef5ff66a2d166b1/protobuf-3.20.1.tar.gz#sha256=adc31566d027f45efe3f44eeb5b1f329da43891634d61c75a5944e9be6dd42c9 (from https://pypi.org/simple/protobuf/) (requires-python:>=3.7)
ERROR: Could not find a version that satisfies the requirement protobuf==3.20.1 (from versions: 2.0.0b0, 2.0.3, 2.3.0, 2.4.1, 2.5.0, 2.6.0, 2.6.1, 3.0.0a2, 3.0.0a3, 3.0.0b1, 3.0.0b1.post1, 3.0.0b1.post2, 3.0.0b2, 3.0.0b2.post1, 3.0.0b2.post2, 3.0.0b3, 3.0.0b4, 3.0.0, 3.1.0, 3.1.0.post1, 3.2.0rc1, 3.2.0rc1.post1, 3.2.0rc2, 3.2.0, 3.3.0, 3.4.0, 3.5.0.post1, 3.5.1, 3.5.2, 3.5.2.post1, 3.6.0, 3.6.1, 3.7.0rc2, 3.7.0rc3, 3.7.0, 3.7.1, 3.8.0rc1, 3.8.0, 3.9.0rc1, 3.9.0, 3.9.1, 3.9.2, 3.10.0rc1, 3.10.0, 3.11.0rc1, 3.11.0rc2, 3.11.0, 3.11.1, 3.11.2, 3.11.3, 3.12.0rc1, 3.12.0rc2, 3.12.0, 3.12.1, 3.12.2, 3.12.4, 3.13.0rc3, 3.13.0, 3.14.0rc1, 3.14.0rc2, 3.14.0rc3, 3.14.0, 3.15.0rc1, 3.15.0rc2, 3.15.0, 3.15.1, 3.15.2, 3.15.3, 3.15.4, 3.15.5, 3.15.6, 3.15.7, 3.15.8, 3.16.0rc1, 3.16.0rc2, 3.16.0, 3.17.0rc1, 3.17.0rc2, 3.17.0, 3.17.1, 3.17.2, 3.17.3, 3.18.0rc1, 3.18.0rc2, 3.18.0, 3.18.1, 3.19.0rc1, 3.19.0rc2, 3.19.0, 3.19.1, 3.19.2, 3.19.3, 3.19.4, 4.0.0rc1, 4.0.0rc2, 4.21.0rc1, 4.21.0rc2, 4.21.0)
ERROR: No matching distribution found for protobuf==3.20.1

I understand Python 3.6 was dropped intentionally in #9480 , but it looks like the step to no longer build and release unsupported/unusable wheels for that version might have been missed.

[haberman]

This should be fixed in the 4.21.1 release.

[ramanathan831]

4.21.1 is available only for python>=3.7, how does then it fix the python3.6 issue @haberman

[cliffwoolley]

@ramanathan831 -- it fixes the issue by not incorrectly announcing that it supports py36 it when it doesn't.

[emay12]

im still experiencing this issue

[doug65536]

Wow, so what version does still support 3.6? mysql-connector needs it.

[jordaniversen]

Anyone find an answer for this?

[cliffwoolley]

@jordaniversen The answer is that if you want py3.6 support from protobuf, you need to pin to the last version that actually supported it (i.e., protobuf<3.20).

[tjmehta]

pip install -v "protobuf<3.20" for python 3.6

[JessicaLopezEspejel]

pip install -v "protobuf<3.20" for python 3.6

Thank you @tjmehta , it also works for Python 3.11.4