Apple started rolling out iOS 15.4 earlier this week, alongside iPadOS 15.4, watchOS 8.5, macOS Monterey 12.3, tvOS 15.4, and HomePod Software 15.4. 

According to GSM Arena, a growing number of people are reporting bad battery life after the OTA. These reports include an iPhone 13 Pro Max only lasting for half a day or an older iPhone 11 dropping 80 percent battery charge in 24 hours with two hours of screen on time. 

Of course, the issue is far from universal, and some temporary battery woes are sometimes expected after an update. Some users have theorised that Apple has started using the max 120Hz ProMotion refresh rate a lot more frequently. It sounds plausible, but it can’t be the full explanation since only the iPhone 13 Pro and Pro Max have ProMotion, and these are not the only affected models. 

Unfortunate battery troubles aside, iOS 15.4 does also include over 100 new emojis from the Emoji 14.0 set, a new voice option for Siri along with the ability to provide time and date information offline, EU Digital COVID Certificate support in vaccine cards in Apple Wallet, improvements to Safari web page translations with support for Italian and Chinese, Podcasts app improvements, and more. 

iOS 15.4 software update enables iPhone users to unlock their devices while having face masks on. The new update, iOS 15.4, released on Monday also includes a host of other features for existing iPhones. The new feature allowing users to unlock their iPhone handsets using Face ID while having masks on is exclusive to iOS 15.4 ‌‌and only available on iPhone 12‌‌, 12 Mini, 12 Pro, and 12 Pro Max, and iPhone 13, 13 Mini, 13 Pro, and 13 Pro Max. 

Once the device is updated, users will see the option to use Face ID with a mask on the welcome screen, the statement said.