Apple has announced that it is offering a $50 credit to any customers who paid for out-of-warranty battery replacements in 2017 for the iPhone 6 or later.
Apple is presumably rolling out the credit to compensate users who purchased battery replacements for affected iPhone models before Apple began offering $29 battery replacements at the end of 2017 to address the issue with deteriorating batteries slowing down older iPhone models.
Apple notes that the credit will be provided as an electronic funds transfer or a credit on the credit card that was used to pay for the battery replacement service, and adds that it will be contacting eligible customers directly via e-mail from now until July 27, 2018, but adds that users who believe they are eligible for a credit should contact Apple directly if they do not receive an e-mail by August 1, 2018.