Ionic serve --lab not working Ionic 4

Ionic Framework
1

No matter what I try, I can’t get ionic-lab to load. Just upgraded to the latest cli and now I can’t test devices.

Ionic:

   Ionic CLI                     : 5.4.7 (/usr/local/lib/node_modules/ionic)
   Ionic Framework               : @ionic/angular 4.11.5
   @angular-devkit/build-angular : 0.801.3
   @angular-devkit/schematics    : 8.1.3
   @angular/cli                  : 8.1.3
   @ionic/angular-toolkit        : 2.1.1

Cordova:

   Cordova CLI       : 9.0.0 (cordova-lib@9.0.1)
   Cordova Platforms : browser 5.0.4, ios 4.5.5
   Cordova Plugins   : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 4.1.3, (and 5 other plugins)

Utility:

   cordova-res : not installed
   native-run  : not installed

System:

   ios-deploy : 1.9.4
   NodeJS     : v10.15.3 (/usr/local/bin/node)
   npm        : 6.4.1
   OS         : macOS Catalina
   Xcode      : Xcode 11.1 Build version 11A1027
2

similiar issue with 4222. Downgrading to 5.4.6 solves the problem.