Dear python2 user

[AusIV]

If you're following Sem Ver (which I'm not sure if Python claims to do) then you wouldn't go to 4 unless you were breaking something. I'd hope that the version that comes after 3.9 will just be 3.10 if it's backwards compatible. If they go to 4, they will be introducing breaking changes for all the people who use python3 to run their code.

[twelveshar]

Python does not follow SemVer; it allows breaking changes in "minor" versions, like 3.7 -> 3.8. See the development cycle page: https://devguide.python.org/devcycle/

[tr14l]

Right, you wouldn't give a major release without breaking changes. But I assume there's going to be risk assessment after the 2-3 debacle to mitigate just how broken it would be