anchor.diff:    };
     serverPreview = mkServer {
       stable = false;
  -    sha256Hash = "03s2kq5f8whk14rhprg9yp3918641b1cwj6djcbjw8xpz0n3w022";
  +    sha256Hash = "0inj6fac0683s1sxaba3ljia90cfach0y42xylzgzza36wpyqpqg";
     };
   }
  
positive.code: 
  let
    stableVersion = "2.1.21";
    previewVersion = "2.2.0rc4";
    addVersion = args:
      let version = if args.stable then stableVersion else previewVersion;
          branch = if args.stable then "stable" else "preview";
  
negative.code:   };
    guiPreview = mkGui {
      stable = false;
      sha256Hash = "0x4sp6yjnvzpk8cxdqlf51njckmvvkijdb7rvcb4hvqq1ab6gb2x";
    };
  
    serverStable = mkServer {
  