The CLPI mirror of Quicklisp is outdated
Packages from https://clpi.ultralisp.org/ultralisp/ are at least a year out of date. For example, usocket
is still at v0.8.3, whereas it's at v0.8.6 in Quicklisp. #58 makes this more of a problem—trying to use Quicklisp directly crashes CLPM. You're stuck with old packages unless you vendor or set up your own mirror.