{ callPackages, callPackage, varnish60, varnish70, fetchFromGitHub }: {
  varnish60Packages = rec {
    varnish = varnish60;
    modules = (callPackages ./modules.nix { inherit varnish; }).modules15;
    digest  = callPackage ./digest.nix {
      inherit varnish;
      version = "libvmod-digest-1.0.2";
      sha256 = "0jwkqqalydn0pwfdhirl5zjhbc3hldvhh09hxrahibr72fgmgpbx";
    };
    dynamic = callPackage ./dynamic.nix  {
      inherit varnish;
      version = "0.4";
      sha256 = "1n94slrm6vn3hpymfkla03gw9603jajclg84bjhwb8kxsk3rxpmk";
    };
  };
  varnish70Packages = rec {
    varnish = varnish70;
    modules = (callPackages ./modules.nix { inherit varnish; }).modules19;
    digest  = callPackage ./digest.nix {
      inherit varnish;
      version = "6.6";
      sha256 = "0n33g8ml4bsyvcvl5lk7yng1ikvmcv8dd6bc1mv2lj4729pp97nn";
    };
    dynamic = callPackage ./dynamic.nix  {
      inherit varnish;
      version = "2.4.0";
      sha256 = "1g53zblyxi1jivwppmpdqhi5xnzapsfib453sxyqbc5dfs7fijxr";
    };
  };
}