anchor.diff:  
       src = fetchurl {
         url = "https://releases.mattermost.com/${version}/mattermost-${version}-linux-amd64.tar.gz";
  -      sha256 = "06dg0f6nrh3a2v3lnyn2s39nj5jpsvfkx3ypq4zjpks0srv4mgfz";
  +      sha256 = "0rxbgd3cb9m7rf0yg1vpd1af6x6bn0jilb0pfqr46dg42a70dx09";
       };
   
       installPhase = ''
  
positive.code: { stdenv, fetchurl, fetchFromGitHub, buildGoPackage, buildEnv }:
  
  let
    version = "5.4.0";
  
    mattermost-server = buildGoPackage rec {
      name = "mattermost-server-${version}";
  
negative.code:       owner = "mattermost";
        repo = "mattermost-server";
        rev = "v${version}";
        sha256 = "1k4rd8383bz9q23wgxnqcp69hcixaa0zd256h54wmwqw6fdn3bc0";
      };
  
      goPackagePath = "github.com/mattermost/mattermost-server";
  