anchor.diff:  , enableSystemd ? stdenv.isLinux
   , systemd
   }:
  +let
  +  nix_version = lib.removeSuffix nix.VERSION_SUFFIX nix.version;
  +  useNlohmann = lib.versionAtLeast "2.7" nix_version;
  +in
  +
  +assert useNlohmann -> nlohmann_json != null;
   
   stdenv.mkDerivation rec {
     pname = "packagekit";
  -  version = "1.2.5pre";
  +  version = "1.2.5.1pre";
   
     outputs = [ "out" "dev" "devdoc" ];
   
     src = fetchFromGitHub {
       owner = "PackageKit";
       repo = "PackageKit";
  -    rev = "9c2ef9cddf39ebde587907561f8e7ac99ed6be1a";
  -    sha256 = "05z1ds240kcmigygkbgjasr4spn7vd7cbpsbfrghhgnmszx9bjgl";
  +    rev = "33b847c49b4a42499e3c0f10fef62830c874e086";
  +    sha256 = "UDpMswf0EBwcoHTqoWiztXnIAwM69nM+S9MPsR24amw=";
     };
   
     buildInputs = [
  
positive.code: , vala
  , gtk-doc
  , nix
  , boost
  , meson
  , ninja
  
negative.code:     nix
      boost
    ] ++ lib.optional enableSystemd systemd
    ++ lib.optional useNlohmann nlohmann_json
    ++ lib.optional enableBashCompletion bash-completion;
    nativeBuildInputs = [
      vala
  