Before B4XPages it was recommended to use Activity.Finish rather than ExitApplication to end an app, but B4XPages don't always have an Activity object so what is now recommended to terminate them?
The term "terminate" is not accurate. The app isn't terminated, it only moves to the background.
You can call B4XPages.ClosePage(Me) to close the current page. If it is the only page in the stack then the app will move to the background.
You can move the app to the background with B4XPages.GetNativeParent(Me).Finish