Apple this morning acknowledged the bug whereby if you change your date to May 1970 or earlier, you won't be able to restart your iOS device. The bug affects all iOS devices that utilize a 64-bit chipset.
As a reminder, the bug in the operating system simply relies on a user resetting a device’s date to any date earlier than May 1970 (earlier reported as just January 1 1970). Once set, if the device gets rebooted it gets permanently stuck. Connecting it to a PC in iTunes or booting into DFU mode seems to work but doesn’t actually fix the problem; the device remains bricked. In fact, except for some random anecdotal evidence, there doesn’t seem to be much that a user can do to fix the issue. Some have suggested the device recovers by itself after a number of hours, while others claim to have had success in reviving their phones by switching out the SIM card.
In any case, some people have also tried to rope users in with various graphics claiming that setting the date to January 1, 1970 will unlock an Easter Egg within iOS and set a "classic Macintosh theme". Although this bug won't do anything on non-64-bit chip iOS devices, anything from an iPhone 5S to the most recent 6s Plus, as well as all iPads starting with the original Air, and recent gen iPod touch will get "bricked" if you apply one of the problematic dates. In terms of operating systems, the flaw has reportedly been confirmed on all versions of iOS from 8.0 up to 9.3.
The post on Apple's site states that "an upcoming software update will prevent this issue from affecting iOS devices" and that if you have this issue, to contact Apple Support.