Hey George,
1st: Are you talking about the App icons? AirWatch is not able to update app icons automatically at the moment, you can still upload them manually or I even think there is an SQL script if you're on-premise.
The device will download the newest app version regardless of the icon so the apps are only visually out of date.
2nd: You need to manually activate auto updates in AirWatch once you added an app via VPP. To do that, just go to Apps >> Native >> Purchased, select the app and click on Enable Auto-Updates. You can also update apps manually by selecting an app and clicking Update app, if you dont want auto updates.
cheers!
Max