I have (HAD) thee same issue.
I posted ths
I have a Ipad 4. After downloading the latest IOS 10 it started shutting down the app i was in and returning to the home screen. I was on the phone for 2 hours with apple support. Made a appointment at the store to restore everything. Went home and had the same problem. Went back to the store. Was told that there was a problem in in the IPad and exchanged it plus cash for a refurbed IPad. Went home and had the same problem on the "new" one. took it back and was told that the Ipad's RAM could not handle the new version of ISO 10. That IPad's generation is only 2 years old. I can't believe that it is outdated that fast.
If that is the real problem then the store should be getting swamped with customers that have the old IPad. I was talked into buying a new IPad Air 2 For $499 minus $90 trade in and got my money refunded for the refurbed unit that didnt solve the problem. Still frustrated by wasting about 14 hours that it took to "resolve" my problem and that doesn't include the time it took for 80 mile round trip to the store that I did 3 times.
The old one was great and worked until the new ISO was downloaded.