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