This is a little-appreciated benefit of using Common Lisp: the language is both standardised and stable, so a library from 2000 is very nearly as likely to run on an implementation today as it was then, or as another library is now.

I do wish that there'd been a newer standardisation effort since, for a couple of reason, but it's really, really nice that the people haven't had to waste effort updating working code to deal with language changes.