Spec 0 is a voluntary set of best practices adopted my many of the most important scientific python projects. It promotes the following:
This SPEC recommends that all projects across the Scientific Python ecosystem adopt a common time-based policy for dropping dependencies. From the perspective of this SPEC, the dependencies in question are core packages as well as older Python versions.
All versions refer to feature releases (i.e., Python 3.8.0, NumPy 1.19.0; not Python 3.8.1, NumPy 1.19.2).
Specifically, we recommend that:
Support for Python versions be dropped 3 years after their initial release.
Support for core package dependencies be dropped 2 years after their initial release.