If you are a registered developer then you can download iOS 11.2 either through Apple’s Developer Center or over-the-air. It can be done once the proper profile has been configured from the Developer Center.
Initially this week, Apple had released its iOS 11.2 to developers and public beta testers. At the same time, it was not made available for iPhone X. Thus, due to this all those customers who had installed the iOS 11.2 beta on their previous devices were unable to restore from an existing backup on the new iPhone X. iPhone iOS 11.2 can be installed on the device after upgrading to the new version of the software.
The sources revealed that iOS 11.2 addressed an animation bug in the Calculator. This made some numbers and symbols to be ignored when entered in rapid succession. Therefore, now the animation has been removed from the updated version. So now the calculations can be easily done without pause between entering numbers to obtain the correct result.
iOS 11.2 introduces a new Now Playing option with the calculator bug. Now Playing option lets you control the content on the Apple TV in Control Center, redesigned camera emoji, and a new loading animation for Live Photos effects.
Source: Mac Rumors