anchor.diff:  
   let
     stableVersion = "2.0.3";
  -  previewVersion = "2.1.0rc1";
  +  previewVersion = "2.1.0rc2";
     addVersion = args:
       let version = if args.stable then stableVersion else previewVersion;
           branch = if args.stable then "stable" else "preview";
  
positive.code:   };
    guiPreview = mkGui {
      stable = false;
      sha256Hash = "0rmvanzc0fjw9giqwnf98yc49cxaz637w8b865dv08lcf1fg9j8l";
    };
  
    serverStable = mkServer {
  
negative.code:   };
    serverPreview = mkServer {
      stable = false;
      sha256Hash = "0vm4hir8yqj7xhykgg3x5rv1nj1qq6sg19sjj7r5w60brrlsw7v9";
    };
  }
  