anchor.diff:    passthru = {
       srcVerification = fetchurl rec {
         failEarly = true;
  -      urls = tarballUrls "1.20";
  +      urls = tarballUrls "1.21";
         inherit (src) outputHashAlgo;
  -      outputHash = "c93b81a5a7788ef5812423d311345ba5d3bd4f5ebf1f693911e3a13553c1290c";
  +      outputHash = "e48b5039d3164d670791f9c5dbaa832bf2df080cb1fbb4f33aa7b3300b670d8b";
         fullOpts = {
           pgpsigUrls = map (n: "${n}.sig") urls;
           pgpKeyFingerprint = "1D41 C14B 272A 2219 A739  FA4F 8FE9 9503 132D 7742";
  
positive.code:     "mirror://savannah/lzip/lzip-${version}.tar.gz"
    ];
  
    version = "1.20";
  in
  stdenv.mkDerivation rec {
    name = "lzip-${version}";
  
negative.code:   src = fetchurl {
      urls = tarballUrls version;
      hashOutput = false;
      sha256 = "e48b5039d3164d670791f9c5dbaa832bf2df080cb1fbb4f33aa7b3300b670d8b";
    };
  
    configureFlags = [
  