My 5th Play through and reinstall, this time playing with WiFi off.
Running:
iPad Air 2
iOS 8.3
I'm now currently up to 80+ Dwellers now. Game is still progressing.
so far the game crashed on me once, but I was able to restart the game with my vault intact, which was a suprise.
Normally, the crashes have happend when I've had between 20-40 dwellers, with WiFi on.
(I've noticed the frequent issues when connected to my home WiFi network for instance,
then taking the iPad away from the local network (being at work), playing with no connection then coming back home with a connection.)
If anyone else is willing to put this to the test, let me know!