After launching a repair program for some iPhone 6s users experiencing unexpected shutdowns, Apple has finally added a serial number checker to the program page, making it much easier for customers to check whether their device is eligible for a free battery replacement (via MacRumors).
Previously, users were able to self-determine if their device was eligible by checking the 4th and 5th characters in their device serial number, by going to Settings > General > About. Eligible devices should see the following characters in their serial numbers:
Apple’s program says if existing users had already paid for a battery replacement, the company will refund the cost.
You can click here to check out the iPhone 6s repair page and check if your serial is eligible or not.