There have indeed been multiple people complaining about crashes on both Android and iOS.
Unfortunately there is very little we can do about it.
You can report a bug in the app by going Menu > Help > Contact > Report a Bug.
If your app doesnt even load to the point where you can report a bug, you can also use https://www.warzone.com/ReportBug
(but prefered method is via the app cause its sends debug data).