anchor.diff:  
       src = fetchurl {
         url = "https://releases.mattermost.com/${version}/mattermost-${version}-linux-amd64.tar.gz";
  -      sha256 = "19ys5mwmw99fbj44gd00vrl2qj09lrwvj1ihic0fsn6nd3hnx3mw";
  +      sha256 = "13xmc2y4pp0b0svzaf4v7ynx6rxcvznx3vqmlrpiil414s69xv45";
       };
   
       installPhase = ''
  
positive.code: { stdenv, fetchurl, fetchFromGitHub, buildGoPackage, buildEnv }:
  
  let
    version = "5.9.0";
  
    mattermost-server = buildGoPackage rec {
      pname = "mattermost-server";
  
negative.code:       owner = "mattermost";
        repo = "mattermost-server";
        rev = "v${version}";
        sha256 = "1bh53h0bmpc1qmnbpsmwkfrvj66z18m7b1xg7pqikid57ssqxjx9";
      };
  
      goPackagePath = "github.com/mattermost/mattermost-server";
  