The problem is affecting "a very small number" of iPhones and means the phone keeps suffering from unexpected shutdowns.
It’s a global repair offer, so if you’re having problems with your iPhone 6S battery you’re going to want to make the most of this offer.
A big fault
Apple released a statement which reads, “Apple has determined that a very small number of iPhone 6S devices may unexpectedly shut down.
"This is not a safety issue and only affects devices within a limited serial number range that were manufactured between September and October 2015.”
If you think your iPhone 6S has been suffering from these issues, you can either visit an Apple Store or an Apple Authorized Service Provider to check the device serial number is one of the devices affected.
It’s a free service and Apple should replace the battery in no time if you’re one of those affected.
If you are eligible for the battery replacement you’ll need to make sure your phone isn’t damaged in any other way before Apple can do the update.
Plus you should back it up and turn off the "Find My iPhone" feature before you give it over to Apple.
- Fancy a new iPhone instead? How about the iPhone 7?
Get daily insight, inspiration and deals in your inbox
Get the hottest deals available in your inbox plus news, reviews, opinion, analysis and more from the TechRadar team.
James is Managing Editor for Android Police. Previously, he was Senior Phones Editor for TechRadar, and he has covered smartphones and the mobile space for the best part of a decade bringing you news on all the big announcements from top manufacturers making mobile phones and other portable gadgets. James is often testing out and reviewing the latest and greatest mobile phones, smartwatches, tablets, virtual reality headsets, fitness trackers and more. He once fell over.