Another US carrier pushes out the update to Android 9 Pie to its Samsung Galaxy S9 and S9+ units.
Once you install the new software, which comes in as a 2GB download, you’ll be on build number G960UOYN3CSAB for the S9, and G965UOYN3CSAB for the S9+.
If you’re impatient you can manually check for the update through settings. The January 2019 security patches should be built in, alongside everything that’s new in Android 9 Pie and Samsung’s revamped One UI. All in all, this is definitely not an update you’d want to miss.