Apple has released iOS 13.4.1. and iPadOS13.4.1 to fix the bugs in iOS and iPadOS 13.4 that was released two weeks ago.
iPhone and iPads get a fix for a bug that prevented devices running iOS and iPadOS 13.4 from making FaceTime calls with devices running iOS 9.3.6 and earlier or with Macs running OS X El Capitan 10.11.6 and earlier.
There’s also a fix for a bug with the Settings app which prevented Bluetooth from being launched from the quick actions menu on the Home screen.
iPad Pro 12.9-inch (4th generation) and iPad Pro 11-inch (2nd generation) users get an additional fix in the form of a patch for a bug that prevented the flashlight from switching on after tapping the Flashlight button in Control Center or on the Lock screen.
As of the time of writing, Apple has not disclosed whether this update contains any security fixes.
Updates can be downloaded over the air by going to Settings > General > Software Update. The download is around 100MB.