anchor.diff:  { stdenv, fetchurl, fetchFromGitHub, buildGoPackage, buildEnv }:
   
   let
  -  version = "5.3.0";
  +  version = "5.4.0";
   
     mattermost-server = buildGoPackage rec {
       name = "mattermost-server-${version}";
  
positive.code: 
      src = fetchurl {
        url = "https://releases.mattermost.com/${version}/mattermost-${version}-linux-amd64.tar.gz";
        sha256 = "1yzhy37frbhik6iq5z8bglpfcjlwnbgcf5iy1davkh7iqpcbxb0s";
      };
  
      installPhase = ''
  
negative.code:       owner = "mattermost";
        repo = "mattermost-server";
        rev = "v${version}";
        sha256 = "0sal5ydm1cwnvf3acmiy0400ghhd6v0wj64mkxqwqf8ysnbxizwq";
      };
  
      goPackagePath = "github.com/mattermost/mattermost-server";
  