It is now possible to download iOS 11 and 11.1.2 jailbreak for iPhone X, 8, and 7, as well as other 64-bit devices. This one is called LiberiOS, which is a semi-tethered jailbreak tool. It is also the first iOS 11 public jailbreak after its debut that can be traced back in September 2017.
The said jailbreak was triggered by the publication of Google’s Ian Beer talking about a vulnerability of iOS 11 and its succeeding versions. Thus, a number of talented people, including Jonathan Levin, were able to do their job, resulting to the release of LiberiOS for iOS 11 through iOS 11.1.2.
LiberiOS was based on the exploit discovered by Beer, and was released for the community as what Levin promised. However, there are warnings related to its instability as a jailbreak tool. For this reason, it would provide easy and immediate access to Substrate and Cydia due to its inability to give SSH and root access. Both were required to install tweaks and packages easily via a simple graphical user interface.
The fact that Cydia wasn’t able to work properly was because it was updated to work on 64-bit devices only. Thus, the completion would depend on when Saurik is able to make it fully compatible with iOS 11.
LiberiOS was able to provide jailbreak to all 64-bit devices that are running iOS 11 through iOS 11.1.2. Therefore, it wouldn’t support devices running before the iOS 11.0 devices or later than iOS 11.1.2. Automatically, it wouldn’t work for iOS versions before 11.0 or even after iOS 11.1.2.
Take note that Apple has stopped signing iOS 11.0 through 11.1.2. Therefore, if you are not yet running the said iOS versions, it would be impossible to downgrade from iOS 11.2.x in order to jailbreak.