Guix let's you create "inferior" channels that are pinned to older channel commit(s) and build packages from them into your system, so if you have a particular

Guix let's you create "inferior" channels that are pinned to older channel commit(s) and build packages from them into your system, so if you have a particular package that's broken beyond a point, you can still pin it and roll everything else forward. I do wish there was a branch that was pinned to eg. the latest commit with a successful CI build of the Guix installer, but CI load is currently it's own issue, so I'd be as happy to see a mechanism for creating your own CI that merges master like weekly and runs custom tests (a la "guix system test"'s VM-based test suite).