anchor.diff:  
       in
         # Declare the ISO as a build product so that it shows up in Hydra.
  -      runCommand "nixos-iso-${version}"
  +      runCommand "nixos-iso-${config.system.nixosVersion}"
           { meta = {
               description = "NixOS installation CD (${description}) - ISO image for ${system}";
               maintainers = map (x: lib.getAttr x lib.maintainers) maintainers;
  
positive.code:       releaseTools.makeSourceTarball {
          name = "nixos-channel";
  
          version = builtins.readFile ./.version;
  
          src = nixosSrc;
  
          inherit officialRelease versionSuffix;
  
          buildInputs = [ nixUnstable ];
  
  
negative.code: 
      let
  
        versionModule =
          { system.nixosVersion = version + (lib.optionalString (!officialRelease) versionSuffix);
            isoImage.isoBaseName = "nixos-${type}";
          };
  
  