Apple releases iOS and iPadOS 13.4.1
https://arstechnica.com/gadgets/2020/04/apple-releases-ios-and-ipados-13-4-1/
In a surprise push today, Apple has released a software update for iPhones, iPads, and iPods that are supported by iOS 13. Today's iOS and iPadOS 13.4.1 releases are focused on bug fixes.
Most notably, they address a problem caused by iOS/iPadOS 13.4 wherein users running that version could not join FaceTime calls with users running older versions of iOS or macOS—iOS 9.3.6 or OS X 10.11.6 or earlier, to be specific. Users began reporting the issue shortly after iOS 13.4 launched, and the timing was unfortunate given that users have been seeking digital ways to connect with family and friends amidst shelter-in-place orders across the world. Apple claims this issue is now fixed.