In November, Apple announced the company would begin replacing some iPhone 6S batteries that were causing the phone to randomly power off for an unknown reason. According to Apple, the issue is limited to devices manufactured between September 2015 and October 2015.
On Thursday, the company published a website for iPhone 6S owners to check if the serial number of a device is eligible for the free battery replacement, as reported by MacRumors.
Visit this tool and enter your serial number to see if your device is eligible for a free battery replacement.
You can find the serial number in Settings > General > About on your iPhone.
The page also includes instructions for those effected by the issue, including links to find the closest authorized service provider or Apple Store.