Apple today released iOS 15.4.1 and iPadOS 15.4.1, minor updates to the iOS and iPadOS 15operating systems that were released in September. iOS 15.4.1 and iPadOS 15.4.1 come two weeks after the launch of iOS 15.4.

The iOS 15.4.1 and iPadOS 15.4.1 updates can be downloaded for free and the software is available on all eligible devices over-the-air in the Settings app. To access the new software, go to Settings > General > Software Update.

According to Apple's release notes, the update fixes an issue that could cause the battery to drain more quickly than expected after updating to iOS 15.4. It also includes fixes for Made for iPhonehearing devices and Braille devices. 

This update includes the following bug fixes for your iPhone:
Battery may drain more quickly than expected after updating to iOS 15.4
Braille devices may become unresponsive while navigating text or displaying an alert
Made for iPhone hearing devices may lose connection within some third-party apps

iOS and iPadOS 15.4.1 fix an AppleAVD issue that could allow an application to execute arbitrary code with kernel privileges. Apple says this exploit may have been actively exploited, so it is a good idea for all users to update as soon as possible. 

Apple has also released new tvOS 15.4.1, HomePod 15.4.1, and watchOS 8.5.1 updates to go alongside the iOS 15.4.1 update.