There have been a number of reports about the January 1st 1970 iPhone Bug over the last week, the bug happens when the date on your device is changed to the above date.
This cause the handset to be totally bricked and now Apple has acknowledged the problem and has said that a fix for the iPhone Bug will be released in a future software update.
Manually changing the date to May 1970 or earlier can prevent your iOS device from turning on after a restart. An upcoming software update will prevent this issue from affecting iOS devices. If you have this issue, contact Apple Support.
It is not clear as yet on whether the fix will come in iOS 9.3 or whether Apple will release another update before that one, as soon as we get some more information, we will let you guys know.