No User Affinity iPads - VPP Automatic Updates Off

We have a cohort of iPads with no user affinity. The apps are delivered via VPP as required. 

Question is the vendor has recently updated an app x and we wish to deploy the update out to all the ipads. What is the best way to do this. 

E.g Open up VPP for automatic updates?  or Uninstall the current version of the app and resync the new version to push out