anchor.diff:    };
     serverPreview = mkServer {
       stable = false;
  -    sha256Hash = "181689fpjxq4hy2lyxk4zciqhgnhj5srvb4xsxdlbf68n89fj2zf";
  +    sha256Hash = "0vm4hir8yqj7xhykgg3x5rv1nj1qq6sg19sjj7r5w60brrlsw7v9";
     };
   }
  
positive.code:   };
    guiPreview = mkGui {
      stable = false;
      sha256Hash = "0rmvanzc0fjw9giqwnf98yc49cxaz637w8b865dv08lcf1fg9j8l";
    };
  
    serverStable = mkServer {
  
negative.code: 
  let
    stableVersion = "2.0.3";
    previewVersion = "2.1.0rc2";
    addVersion = args:
      let version = if args.stable then stableVersion else previewVersion;
          branch = if args.stable then "stable" else "preview";
  