Python packaging targets

If it's Debian we are talking about, and if the upgrade itself is source-compatible (which was assumed upthread) then creating a backport isn't much more difficult than pip-installing something: just download the source .deb, unpack it, install the build depencencies (which you must, perhaps, tweak to reflect what you have on your stable), perhaps tweak some dependencies, then dpkg-buildpackage.

Compared with some boxes I meet regularly at work, which are "lots of little .venv directories, all alike", this might be a nicer option, after all.