iOS 15.4 has been released about two weeks ago, and some users have been reporting problems with the battery draining quickly and running water. Apple has released iOS 15.4.1 as an ad hoc update to fix the problem for the iPhone. This includes iPadOS 15.4.1 for iPad. A security vulnerability has also been addressed from AppleAVD that could allow apps to execute arbitrary code using kernel privileges. We recommend immediate updates if possible.
In addition to the above, iOS 15.4.1 includes some additional bug fixes, including connectivity issues with Made for iPhone hearing aids and braille devices that sometimes become unresponsive.
Friends can update iOS 15.4.1 and iPadOS 15.4.1 by going to Settings > General > Software Update.
source: MacRumors
