Python never claimed to be semver-compliant. Also, if you’re using 3rd-party packages that require compiling stuff (eg. numpy), pre-built binary packages (aka w

Python never claimed to be semver-compliant. Also, if you’re using 3rd-party packages that require compiling stuff (eg. numpy), pre-built binary packages (aka wheels) might not be available on PyPI in the first few days (or weeks, or sometimes even months) after Python 3.x.0 is released, so you don’t want the version to be randomly changed under you. Moreover, I pulled python:3 a year ago, so I get 3.9. FROM python:3.10 should generally be fine though.