pip always uses the highest compatible version

[rbtcollins]

However for testing it would be great to be able to invert pips preferences for versions and have it pick oldest-compatible rather than newest. Clearly a security risk, but great for making sure the minimum version actually works.

[dstufft]

Closing this. While I can see a general use case for it, I feel like the feature itself will be confusing to most people and will be a bit of a footgun for them. I think a better way to solve this is a tox environment or similar that just maintains pins to your minimum version.