iOS Update 13.4.1
The iOS 13.4.1 includes bug fixes for your Apple iPhone.
This update fixes an issue where devices running iOS 13.4 could not participate in FaceTime calls with devices running iOS 9.3.6 and earlier or OS X El Capitan 10.11.6 and earlier.
This iOS update addresses a bug with the the Settings app where choosing Bluetooth from the quick actions menu on the Home screen would fail.
For more information on the security content of this particular Apple software update, checkout the Apple Support knowledge base article located at: