let
  pkgs = import ./nix/pkgs.nix {};
  versions = [
    "lts-12.14"
    "lts-12.23"
    "lts-13.19"
    "lts-13.11"
  ];
  mkCi = version:
    let
      nixpkgsVersion = import (./ci + "/${version}.nix");
      pkgsf = import ./nix/nixpkgs.nix { inherit nixpkgsVersion; };
      p = import ./nix/pkgs.nix { inherit pkgsf; };
      target = pkgs.stdenv.mkDerivation {
        name = version;
        nativeBuildInputs = pkgs.lib.attrValues p.validityPackages;
        buildCommand = ''
        '';
      };
    in target;
in pkgs.lib.genAttrs versions mkCi