anchor.diff:          # When the URL disappears, it typically means that Debian has new patches
           # (probably security) and updating to new tarball will apply them as well.
           name = "systemd-debian-patches.tar.xz";
  -        url = mirror://debian/pool/main/s/systemd/systemd_239-11~bpo9+1.debian.tar.xz;
  -        sha256 = "136f6p4jbi4z94mf4g099dfcacwka8jwhza0wxxw2q5l5q3xiysh";
  +        url = mirror://debian/pool/main/s/systemd/systemd_239-12~bpo9+1.debian.tar.xz;
  +        sha256 = "0v9f62gyfiw5icdrdlcvjcipsqrsm49w6n8bqp9nb8s2ih6rsfhg";
         };
         # Note that we skip debian-specific patches, i.e. ./debian/patches/debian/*
       in ''
  
positive.code:   pythonLxmlEnv = buildPackages.python3Packages.python.withPackages ( ps: with ps; [ python3Packages.lxml ]);
  
  in stdenv.mkDerivation rec {
    version = "239";
    name = "systemd-${version}";
  
    # When updating, use https://github.com/systemd/systemd-stable tree, not the development one!
  
negative.code:   src = fetchFromGitHub {
      owner = "NixOS";
      repo = "systemd";
      rev = "nixos-v${version}";
      sha256 = "1m9mhv7b4kfa43z79106gpgxx51zlhvvfjrlmimdsvsiw72nzldj";
    };
  
    prePatch = let
  