Apple has announced a new repair program (http://tinyurl.com/zt3zvf9) for iPhone 6s users whose devices may be unexpectedly shut down. The company says this isn’t a safety issue and only affects devices within a limited serial number range that were manufactured between September and October 2015.
If you have experienced this issue, visit an Apple Retail Store or an Apple Authorized Service Provider and have your device’s serial number checked to confirm eligibility for a battery replacement, free of charge. Your iPhone will be examined prior to any service to verify that it is eligible for this program and in working order.