I know nothing about iPhones but I have just read the following article and it appears there is a hoax that will cause problems if you follow the instructions in the hoax message.
https://nz.news.yahoo.com/technology...a-retro-theme/
"With this Easter egg, warp back in time with a classic Macintosh theme to relive the magic on your iPhone," reads the graphic that mimics the look and feel of an Apple advert.
However, the date change only trips a bug in the operating system that breaks the phone almost beyond redemption. A hard reset will not work, nor will the iTunes reboot.
Apparently the only way to save the device is to have a technician disconnect and reconnect the battery or for the battery drain itself completely flat, a wait of about two weeks.