Establish python version support/drop policy (SPEC0) in v2

[mfisher87]

Hey all, I noticed in a previous post NEP 29 was used justification for dropping Python 3.6. It's been a couple years, and the community (including numpy) is now coalescing around this very similar standard, SPEC0: https://scientific-python.org/specs/spec-0000/

Under SPEC0 and NEP29, we can drop support for 3.7, 3.8, and 3.9. Do we have an official policy?

Also, are we following semantic versioning? We have a v2 branch in progress, and I'm fairly sure dropping support for a Python version justifies a major bump if we are. At least that's what I've seen in practice!

[JessicaS11]

Do we have an official policy?

We do not.

Also, are we following semantic versioning?

It's buried in the release guide, but we do!

We have a v2 branch in progress, and I'm fairly sure dropping support for a Python version justifies a major bump if we are. At least that's what I've seen in practice!

That makes sense and seems like a good opportunity to do this bit of housekeeping.

[mfisher87]

Thanks, Jessica! Does the new issue title seem like accurate and complete?

[weiji14]

Seems like we can drop Python 3.10 as well, so let's drop Python 3.9 and 3.10 (#655) after Python 3.13 support is added in #622

[JessicaS11]

Should we add a note to the docs around using SPEC0 as our standard policy for dropping support of older versions of Python? It sounds like there's general agreement around that and this way it's written down for future devs.

[mfisher87]

Definitely :) That's what I had in mind with the "documentation" label I added, but I should have probably been more explicit!!