According to Daring Fireball’s John Gruber, Cook informed employees of the massive uptick in iPhone battery replacements — 11 million versus an anticipated 1-2 million — during an town hall meeting on Jan. 3.
Tim Cook reportedly stated that Apple replaced 11 million batteries over the duration of the $29 replacement program. During a normal year, Apple plans to replace around between 1 and 2 million batteries, Cook said during the meeting.
The $29 replacement initiative was active for almost exactly a year. This means in 2018, Apple replaced as as high as 11 times the number of batteries it usually replaces in a year.
Apple instituted the replacement program at the end of 2017 in response to revelations that older versions of iOS artificially throttled the performance of iPhones with degraded batteries.
Operating a device with a worn battery can result in shorter running times and, as was the case with certain iPhones, random shutdowns under extreme loads. Apple quietly instituted a performance cap in iOS 10.2.1 to alleviate performance issues and keep older phones operational. Customers were not notified of the change, which led to a major kerfuffle when it was discovered that the peak performance of some iPhones would be artificially reduced under certain situations. A series of lawsuits and probes by governmental bodies followed.
Apple apologized for what it characterized as a “miscommunication” in a letter to iPhone owners in late 2017. The battery replacement program, which was part of Apple’s response, kicked off in January 2018 and ran through December that year.