anchor.diff:  
     rocksdb = fetchgit rec {
       url = "https://github.com/facebook/rocksdb.git";
  -    rev = "v6.5.3";
  -    sha256 = "11kbwqph1i3w6rbhr0kl2aq4jidhai24gw420y9qi9ab7zl0zcqg";
  +    rev = "v6.7.3";
  +    sha256 = "16qb636qs2yxqmz30hmvq8mllf038s80p37b0vyc0bazwlr93d9z";
       deepClone = true;
       fetchSubmodules = false;
       leaveDotGit = true;
  
positive.code:   };
  in stdenv.mkDerivation rec {
    pname = "rippled";
    version = "1.6.0";
  
    src = fetchgit {
      url = "https://github.com/ripple/rippled.git";
      rev = version;
      sha256 = "176i3dm98zp5jllslpzfhh52bd2lapq9i8r7m45v8sg9icvsmyz7";
      leaveDotGit = true;
      fetchSubmodules = true;
    };
  
negative.code: 
    nudb = fetchgit rec {
      url = "https://github.com/CPPAlliance/NuDB.git";
      rev = "2.0.5";
      sha256 = "02zbd07qvdjjsm4ivvhxah5n466bncvm6m03vmq0qdbbrlnp6s37";
      leaveDotGit = true;
      fetchSubmodules = true;
      postFetch = "cd $out && git tag ${rev}";
  