This week, Apple released updates for iOS and iPadOS to fix the issue with FaceTime where users couldn’t call users on iOS 9.3.6 and earlier or OS X El Capitan 10.11.6 and earlier. Earlier this week, iOS 13.4.1 was released for iPhone and iPod touch and iPadOS 13.4.1 was also released for iPad, to fix this issue.

macOS 10.15.4 has now been released which helps fix the same issue, as well as a bug with Office 365 accounts and also and issue where a USB-C port could not work for some reason has also been resolved.

Release Notes

– Fixes an issue where Mac computers running ‌macOS Catalina‌ 10.15.4 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
– Resolves an issue where you may repeatedly receive a password prompt for an Office 365 account
– Fixes an issue where ‌MacBook Air‌ (Retina, 13-inch, 2020) may hang in Setup Assistant or when disconnecting and reconnecting a 4K or 5K external display
– Resolves an issue where a USB-C port in your Mac may become unresponsive

Users already running macOS Catalina can go to System Preferences > Software Update to update their device.