Hi all, As a NixOS user, I have in the past found that I need an older GHC release that is no longer available (or not yet available) in nixpkgs. While mpickering's old-ghc-nix [1] conveniently allows standard GHC binary distributions to be adapted for use under NixOS, I have found that it is less than reliable when building later projects [2]. For this reason, I have started collecting a set of nix expressions for building GHC versions all the way back to GHC 8.4.1 and extending up to GHC 9.0.1-rc1. In addition, there is a binary cache with pre-built binaries (complements of Cachix) here [3]. I intend on continuing to add new releases to this as needed. I hope others also find this helpful. Cheers, - Ben [1] https://github.com/mpickering/old-ghc-nix [2] https://gitlab.haskell.org/ghc/ghc/-/issues/19144 [3] https://app.cachix.org/cache/ghc