Apple's secrecy surrounding the practice is what truly embroiled the company in controversy (and made the company subject to class-action lawsuits), so it slashed the price of battery replacements for the iPhone 6 and newer devices from $79 to $29. However, there has been some confusion as to how "worn" a battery has to be qualify for a replacement.
Earlier reports have suggested that if a battery retains less than 80 percent of its original capacity, it would qualify for replacement. iPhone owners who didn't meet that criteria were reportedly being turned away by Apple Geniuses.
However, Apple has since acknowledged to MacRumors that it will replace iPhone batteries regardless of how they perform on battery diagnostic tests at the Apple Store. So, no matter if your battery is sitting at 90 percent of its original capacity or 50 percent; it doesn't matter. Apple will replace the battery and take your $29 in the process.
This appears to be a move to help placate customers that are irate about the whole battery throttling fiasco, and gives anyone looking to get a factory fresh battery a relatively cheap and painless way to do so.
MacRumors also references anecdotal reports that customers who have previously paid the full $79 for an iPhone battery replacement have received refunds from Apple to match the new, lower price.
Apple introduced a throttling mechanism for the iPhone 6, iPhone 6s and iPhone SE with iOS 10.2.1, and added the iPhone 7 with the iOS 11.2 update. The company has promised to give customers access to more detailed battery health statistics in an upcoming iOS point release.