On November 28th, Apple closed the verification channel for iOS 12.0.1, which was released in early October. This means that downgrading from iOS 12.1 is no longer possible.
Apple has stopped validating iOS 11.4.1 and iOS 12.0.
In fact, demotion demand has slowed down over the years. First, OTA replaces iTunes as the dominant way to upgrade, second, the appeal of jailbreak is reduced, and third, it is difficult for new equipment to have a perfectly solidified prison escape scheme.
Currently, the latest official version of iOS is iOS 12.1, and iOS 12.1.1 is also entering the third beta.
Compared to iOS 12.0.1, the official version of Bug, 12.1 has improved system stability, enabled eSIM support for iPhone XS,XR,XS Max's non-Bank of China (HK) version, and launched FaceTime group chat (up to 32 simultaneous chats). More than 70 new Emoji expressions were added, eliminating the previewing effect and adding a new real-time depth-of-field control function.