anchor.diff:  
   with stdenv.lib;
   let
  -  version = "0.20.0";
  +  version = "0.20.1";
     majorMinorVersion = versions.majorMinor version;
     desktop = fetchurl {
       url = "https://raw.githubusercontent.com/bitcoin-core/packaging/${majorMinorVersion}/debian/bitcoin-qt.desktop";
       sha256 = "0cpna0nxcd1dw3nnzli36nf9zj28d2g9jf5y0zl9j18lvanvniha";
  -  };
  -  pixmap = fetchurl {
  -    url = "https://raw.githubusercontent.com/bitcoin/bitcoin/v${version}/share/pixmaps/bitcoin128.png";
  -    sha256 = "08p7j7dg50jlj783kkgdw037klmx0spqjikaprmbkzgcb620r25d";
     };
   in
   stdenv.mkDerivation rec {
  
positive.code: 
    postInstall = optional withGui ''
      install -Dm644 ${desktop} $out/share/applications/bitcoin-qt.desktop
      install -Dm644 ${pixmap} $out/share/pixmaps/bitcoin128.png
    '';
  
    configureFlags = [
  
negative.code:       "https://bitcoincore.org/bin/bitcoin-core-${version}/bitcoin-${version}.tar.gz"
        "https://bitcoin.org/bin/bitcoin-core-${version}/bitcoin-${version}.tar.gz"
      ];
      sha256 = "4bbd62fd6acfa5e9864ebf37a24a04bc2dcfe3e3222f056056288d854c53b978";
    };
  
    nativeBuildInputs =
  