Why it matters: Apple's iOS 15.4 operating system for iPhones rolled out of beta and into the public domain last week, bringing with it a slew of new features. Sadly for some users, one of the changes is less welcome than others: severe battery drain.

The stable version of iOS 15.4 was released to sixth-generation iPhones and later last week. One of the most talked-about features it adds is the ability for FaceID to recognize faces even when people are wearing masks. It also brings over 100 new emojis, an Apple card widget, a new voice option for Siri, and more. But, as is so often the case with major operating system updates, some users are running into issues that weren't there before the installation.

Podcaster Alex Kretzschmar was one of several iPhone users to complain about iOS 15.4 impacting their device's battery life. He says the update has caused "mad battery drain" and that "battery life today is half what it was last week."

Other reports include an iPhone 13 Pro Max dropping to half its capacity by mid-day after previously lasting much longer on a single charge and an iPhone 11 losing 80% of its charge in 24 hours despite the user's screen time not exceeding two hours on common apps such as Instagram.

There have been theories that part of the problem is due to iOS 15.4 causing the maximum 120Hz ProMotion refresh rate to be reached a lot more frequently. While that would impact battery life, only the iPhone 13 Pro and Pro Max have the ProMotion feature; the reports cover a wide range of Apple handsets.

It's worth noting that the issue appears to be affecting only a small number of iPhone users, and we've seen similar reports of battery problems following one of Apple's operating system updates in the past, most of which appear to resolve themselves.

Apple has yet to comment on the matter.