Seems like it's time to remove links to outdated versions. Replace them with your resume?

I believe crates doesn't really allow that, partially so that people can't easily sabotage the supply chain like that :)

Correct, you cannot remove a version or the whole crate unless very specific criteria are fulfilled. You can "yank" versions. That prevents people from adding the version as a new dependency, but if you relied on it before it got yanked, your build will succeed.

I wouldn't delete old versions even if I could though. My goal is to publish a rock solid library that everyone can depend on and build awesome projects with