The company has said this is not a safety issue, and it only affects a limited serial number range of devices manufactured between September and October 2015. Users experiencing the problem can visit an Apple retail store or authorized service provider to verify if their iPhone 6S was manufactured during the one-month period. Of course, there are also third-party sites that provide this service free of charge by entering the device’s IMEI number.

In order to prepare for the battery replacement process, all device data must be backed up and erased from the device or the company will not issue a new battery. Unfortunately, customers who have cracked screens may need to have them replaced prior to getting a free battery replacement.

“If your iPhone 6s has any damage such as a cracked screen which impairs the replacement of the battery, that issue will need to be resolved prior to the battery replacement,” says the company’s statement. “In some cases, there may be a cost associated with the repair.”

Last week, Chinese consumer protection group China Consumers Association received reports that some iPhone 6S units had been powering down with over 50 percent charge remaining.

The consequence of a limited production run of faulty iPhone 6S battery units may not prove quite as serious for Apple as the wider recognition of home buttons breaking, often before a user’s warranty has expired. To counteract the company’s steep in-house repair costs, many customers have turned to third-party repair shops to install replacement Home button cable hardware which was, in effect, unrecognized under iOS and rendered many devices into useless bricks.