Apple admitted to the ‘touch disease’ with certain models of iPhone 6 and 6 Plus models and now admitted to having battery issues with the 6S.
iPhones manufactured between September and October 2015, are being offered for battery replacement by Apple company, as various of them were shown to shut down at random. Take the iPhone to the Apple store or Apple service provider and get serial number checked if the mobile was manufactured during that brief period of time.
After checking the serial number it is found that the mobile was from the batch of iPhones having faulty battery, get it replaced free of cost. The battery is covered 3 years after the first retail sale of the iPhone 6S or 6S plus unit.