Using an older Nixpkgs checkout might have a higher rate of success but if Nixpkgs never included the version you need in the first place that also doesn't work

Using an older Nixpkgs checkout might have a higher rate of success but if Nixpkgs never included the version you need in the first place that also doesn't work. Yeah, but also keep in mind that uses the older version, plus older versions of all its transitive dependencies (from the same nixpkgs checkout). So, you could end up with multiple versions of glibc and other commonly-used libraries, but worse -- many known security vulnerabilities as well. Another practical annoyance is that overriding attributes often does not work across a derivation. E.g. overriding the version attribute does not override the same version in the src attribute (which is used to download the sources) [1]. So, you may have to override the attribute in several places. [1] Unless the derivation is defined in a non-canonical way: https://discourse.nixos.org/t/avoid-rec-expresions-in-nixpkgs/8293 https://discourse.nixos.org/t/avoid-rec-expresions-in-nixpkg...