I can't restore back up from PC. I returned to iOS 10.3.3.from iOS 11. Two months ago or earlier I've installed iOS 11 beta. Now I tried to get back to ioS 10.3.3. using recovery mode. I did back up on my PC but after IoS 10.3.3. installing restore back up failed - message: this back up corrupted or does not support .......How shall I proceed? Shall I return back to beta ioS 11? 
Thanks, Maira
Backups of a newer version of iOS can’t be restored onto a device with an older version of iOS. To restore your iOS 11 backup, you’ll need iOS 11 running on the device.