After it was revealed that older iPhone batteries were throttled, Apple created a battery replacement program for customers.
Certain models of the iPhone 6 and iPhone 6s had issues with the battery. Apple started a battery replacement program last year ending soon.
To be eligible, you had to have bought it between January 1, 2017 and December 28, 2018.
The company said a component failure may lead to battery expansion, and that affected devices can get their battery replaced.