anchor.diff:  { stdenv, fetchurl, dpkg, makeWrapper
   , alsaLib, atk, cairo, cups, curl, dbus, expat, fontconfig, freetype, gdk_pixbuf, glib, glibc, gnome3
  -, gtk2, libnotify, libpulseaudio, libsecret, libv4l, nspr, nss, pango, systemd, xorg }:
  +, gtk3, libnotify, libpulseaudio, libsecret, libv4l, nspr, nss, pango, systemd, xorg }:
   
   let
   
     # Please keep the version x.y.0.z and do not update to x.y.76.z because the
     # source of the latter disappears much faster.
  -  version = "8.18.0.6";
  +  version = "8.24.0.2";
   
     rpath = stdenv.lib.makeLibraryPath [
       alsaLib
  
positive.code:     if stdenv.system == "x86_64-linux" then
        fetchurl {
          url = "https://repo.skype.com/deb/pool/main/s/skypeforlinux/skypeforlinux_${version}_amd64.deb";
          sha256 = "193icz1s385d25qzm5vx58h66m4hfwwmkavn0p3w6631gj617hig";
        }
      else
        throw "Skype for linux is not supported on ${stdenv.system}";
  
negative.code: 
      gnome3.gconf
      gdk_pixbuf
      gtk3
  
      gnome3.gnome-keyring
  
  