macOS 10.15 Catalina Supplemental Update is now available (updated)

Apple has today released macOS 10.15 Catalina Supplemental Update, which contains bug fixes and other improvements. It’s just under a gigabyte in size, which is quite substantial for such an early update before the first full update to Catalina.

The update identifies itself not as a Supplemental Update, but as “macOS 10.15 Update” which seems unusually non-specific.

There are no changes in the build numbers of any of Apple’s bundled apps. Minor changes in /System/Library include updates to:

  • iCloudIDAuthentication.bundle
  • iCloudIDNotification.bundle
  • Setup
  • Calendar Setup Assistant Plugin
  • LaunchServices Setup Assistant Plugin
  • QuickLook Setup Assistant Plugin
  • Spotlight Setup Assistant Plugin
  • iCloudDelegate Setup Assistant Plugin
  • GameKit Framework
  • AOS Accounts Frameworks
  • GameCenter Frameworks
  • OS Installer Framework.

According to Mr.Macintosh, these improve installation reliability when storage space is low, ensures that Setup Assistant can complete properly, resolves and issue accepting iCloud terms and conditions with multiple iCloud accounts, and improves saving of Game Center data when playing offline.

There are no signs of firmware updates, or any changes to security data files, apart a strange duplication of XProtect bundles. Following this update, there are now two different XProtect bundles:

  • a writeable bundle on the Data volume in System/Library/CoreServices named XProtect.bundle, which contains version 2106, with the addition of a database file named gk.db in its resources. This also has a symbolic link from the System folder, at /System/Library/CoreServices
  • a read-only folder named “XProtect.bundle 1” which was installed with this update, and is on the System volume at /System/Library/CoreServices. This also appears to contain version 2106, but lacks the database file gk.db in its resources.

It’s hard to know whether the latter of those is an installation error, a fix for a bug, or something new altogether.

I don’t yet have a direct download link, but when I have located one I will post it here.

There are currently no signs of any security updates for earlier versions of macOS.

Thanks to the eagle-eyed Jeff Johnson @lapcatsoftware for spotting this, after I had just checked unsuccessfully for updates.
Last updated 2000 UTC 15 October 2019.