Apple has released a supplemental update for macOS 10.15.4 Catalina (see “Apple Releases macOS 10.15.4 Catalina, watchOS 6.2, tvOS 13.4, and iOS 13.4 for HomePod,” 24 March 2020). As with iOS 13.4.1, the highlight of macOS 10.15.4 Catalina Supplemental Update is a fix for FaceTime problems introduced in the last update. The supplemental update:
- Fixes a bug that prevented Macs running macOS 10.15.4 from engaging in FaceTime calls with devices running iOS 9.3.6 or OS X 10.11.6 El Capitan and earlier.
- Prevents USB-C ports in your Mac from becoming unresponsive.
- Resolves an issue that caused the 2020 MacBook Air to hang in Setup Assistant when disconnecting and reconnecting a 4K or 5K external display.
- Stops Microsoft Office 365 accounts from repeatedly prompting you to enter a password.
The supplemental update has no published CVE entries.
You can install the 1.01 GB macOS 10.15.4 Supplemental Update from System Preferences > Software Update. On his Eclectic Light Company blog, Howard Oakley said, “This is the smallest macOS update that I have ever analysed in detail, suggesting that those bugs were severe in their effects.”
If you’ve already installed macOS 10.15.4 and are likely to run into any of the bugs it fixes, it’s probably worth installing this update soon. Otherwise, you can wait until it’s convenient—as you’ll see in the comments, a few people have anecdotally had problems with it.