What happened to Perl 7?

I've been doing this for years, and it works fine. When a new release of Perl comes out, I read the release notes and see if any nice new features were introduced that might warrant updating the oldest supported Perl version in one or more of my modules.

Personally, I prefer use <version> to explicit use feature anyway since for documentation purposes the minimum supported version is the actually important information. (But I also don't tend to use any experimental features that are off by default.)