As expected, Apple is now rolling out iOS 12.1, watchOS 5.1, tvOS 12.1 and macOS 10.14.1 to the public. Today’s updates bring a slew of new features such as Group FaceTime, dual SIM support for iPhone XS, iPhone XS Max, and iPhone XR, and new emojis.

iOS 12.1 is available on 3uTools now, you can easily upgrade to it. If you don't know much about iOS 12.1 version, please check What's new in iOS 12.1?

Step 1 Connect your device to PC and then launch the latest version of 3uTools. 

Step 2 Click Flash & JB -> Easy Flash, select iOS 12.1  firmware as the following picture. Click"Flash" to start the process. ( If you want to save data, just select the option "Retain User's Data While Flashing" before the flash.)

Step 3 Keep a good connection and internet while flashing. After a few minutes, your iDevice will automatically reboot. Now you can experience iOS 12.1, before the final version.