anchor.diff:  
     src = fetchurl {
       url = "https://updates.signal.org/desktop/apt/pool/main/s/signal-desktop/signal-desktop_${version}_amd64.deb";
  -    sha256 = "1s1rc4kyv0nxz5fy5ia7fflphf3izk80ks71q4wd67k1g9lvcw24";
  +    sha256 = "1gbvna40sc83s7mwip5281yn4bs0k19fj061y0xzwkvh0yk06x3i";
     };
   
     nativeBuildInputs = [
  
positive.code:     # Fix the desktop link
      substituteInPlace $out/share/applications/signal-desktop.desktop \
        --replace /opt/Signal/signal-desktop $out/bin/signal-desktop
    '';
  
    meta = {
  
negative.code:       else "");
  in stdenv.mkDerivation rec {
    pname = "signal-desktop";
    version = "1.30.0"; # Please backport all updates to the stable channel.
    # All releases have a limited lifetime and "expire" 90 days after the release.
    # When releases "expire" the application becomes unusable until an update is
    # applied. The expiration date for the current release can be extracted with:
  