Warning for all #nixos unstable users: borgbackup is broken because they seem to check for the installed msgpack version and somehow rebuilding the derivation installs 1.0.7 instead of the allowed 1.0.6. (nixpkgs list 1.0.5 as current, so wtf) Seems like a bug in `buildPythonApplication` to me. I was not able to get a github checkout in an override to build correctly, so keep your flake version to something before September 28th (release date of msgpack 1.0.7)