iphone6s can't get up to 100% charged
I have my new iPhone 6s in hand.
It only gets up to 98-99% charged.
I tried to unplug and replug it but it still shows as charging but not getting up to 100%.
Is it a battery or hardward or softward problem?
If not, how to get it up to 100% charged?
Many thanks~
iPhone 6s, iOS 9.0.2