anchor.diff:    };
     guiPreview = mkGui {
       stable = false;
  -    sha256Hash = "0hb22z7vd69dq6nayyyndlyqsnxb3lzgw3ac6m3fnxkv18n1nm6v";
  +    sha256Hash = "1bzy95zqinwrrga7qj6gvpzvz34w4ddhvgmpgq3p1lwzixpqg1w7";
     };
   
     serverStable = mkServer {
  
positive.code: 
  let
    stableVersion = "2.1.21";
    previewVersion = "2.2.0b2";
    addVersion = args:
      let version = if args.stable then stableVersion else previewVersion;
          branch = if args.stable then "stable" else "preview";
  
negative.code:   };
    serverPreview = mkServer {
      stable = false;
      sha256Hash = "1bq4ww6qhhl0qw6yj7cf7yg54yb4y8mxlnwss6hgbyfv5fz9rxjp";
    };
  }
  