how to set the year back to 2015 from my Iphone 5 ?

[iMore Question]

after fixing my iphone 5 in changing its LCD. after it seems the icon still on "searching". we found out that the year was fix to 1970 even we set the date&time.. I still used iOS 7.1 version. Please help me ?

 

[kch50428]

Update the iOS.