Timeline for Pint version support

[mattwthompson]

Since Pint is stuck in ZeroVer, it's hard to know when major behavior changes are coming. We should think through version support while we can. Holding on to old versions has not yet been a major problem at runtime, but we have to test against every version we support (alongside an array of Python versions and other optional dependencies)

• 0.26 has no timeline for release as far as I can tell
• 0.25 was released in August 2025, meaning there's been plenty of time for updates to be accounted for (if any)
• 0.24 was released in June 2024, so we're holding onto a version that's two years old now

cc @atravitz, any strong feelings on support old-ish Pint?

[atravitz]

openfe is currently pinned to pint >=24.0 and probably benefiting from openff's upstream pinning and testing rigor. I'm making sure we're good to use 0.25 and 0.26 here, but as long as that passes I think we're alright.