Apple is offering free battery replacements for some iPhone 6s users whose phones are unexpectedly shutting down. The program is limited to certain devices manufactured from September to October 2015, and phones are subject to an inspection prior to the repair to make sure the serial number is within the correct range. Customers can contact Apple technical support, an Apple retail store or an authorized Apple service provider to find out of their phone is eligible for the repair. Owners of an iPhone 6s who have paid to replace their battery to remedy the shut down problem are also urged to contact Apple about a possible refund. Before customers take their phone in for service, Apple recommends backing up all personal data.
Update: Apple has added a serial number checker to the program page, allowing users who suspect they may be affected by this problem to enter their iPhone 6s serial number online to see if their device is eligible for replacement under the program.