Recently I read Itamar Turner-Trauring's It’s time to stop using Python 3.7 (via). On the one hand, this is pragmatic advice, because as the article mentions Python 3.7 is reaching its end of life as of June 2023. On the other hand it gives me feelings, and one of the feelings is that the Python developers are not making upgrades any easier by slowly deprecating various standard library modules. Some of these modules are basically obsolete now, but some are not and have no straightforward replacement, such as the cgi module.

The Python developers can do whatever they want to do (that's the power of open source), and they clearly want to move Python forward (as they see it) by cleaning up the standard library. But this means that they are perfectly willing to break backward compatibility in Python 3, at least for the standard library.

One of the things that make upgrading versions of anything easy is if the new version is a drop in replacement for the old one. Deprecating and eventually removing things in new versions means that new versions are not drop in replacements, which means that it makes upgrading harder. When upgrading is harder, (more) people put it off or don't do it. This happens regardless of what the software authors like or think, because people are people.

I doubt this is a direct factor in people still using Python 3.7. But I can't help but think that the Python developers' general attitude toward backward compatibility doesn't help.

(Python virtual environments make different versions of Python not exactly a drop in replacement; in practice you're going to want to rebuild the venv. But my impression is that pretty much everyone who is seriously using Python with venvs has the tools and experience to do that relatively easily, because their venvs are automatically built from specifications. Someday I need to master doing that myself, because sooner or later we're going to need to use venvs and be able to migrate between Python versions as part of an OS upgrade.)