In short: iPhone users have been eagerly awaiting the release of iOS 15.4 from Apple, which added the ability to use Face ID while wearing a mask. However, a few days after installing it, a small number of people reported reduced battery life. Apple has released a fix.
With release iOS as well as iPadOS 15.4.1 Apple says it has fixed an issue that resulted in reduced battery life on some devices after installing version 15.4. The latest update also includes fixes for braille and hearing devices. Even users who have had no battery life issues should still install it to receive security updates.
Some users reported that their iPhone battery life was reduced by 50 percent after installing iOS 15.4. Apple Support initially tweeted that some issues should be expected in the first couple of days after a firmware update, but some users have reported reduced battery life more than 48 hours after the update.
Some have speculated that the problem was related to the high refresh rate in iPhone models with ProMotion, but the reports were not limited to those models. Others have suggested that it may have something to do with the aging of the batteries. Either way, resolving the problem with an update confirms that it’s a software issue.
To update your iPhone or iPad, go to Settings > General > Software Update.