After last week’s release of the second build, Apple today released the third build of iOS 12.1 for testing on the iPhone and iPad.
Registered beta testers can install the updated build by heading over to Settings > General > Software update. From there, you’ll see the listing for the build. Just tap “Download and install” and wait for your phone or tablet to complete the process. I recommend plugging in your device beforehand so you don’t run out of power before the installation is complete.
In iOS 12.1, group FaceTime calls come back along with bug fixes and security enhancements. We’ll let you know of any other notable features as time progresses.