With the release of Ian Beer's new exploit, some hope for a future Apple TV 4/4K jailbreak has appeared. The exploit will theoretically work on firmwares up to and including tvOS 11.1, but not 11.2 and higher. For this reason, I advised in my jailbreak guide that Apple TV 4/4K users who want to have a chance of jailbreaking manually restore now to tvOS 11.1, before it goes unsigned. You can use our guide on the topic to do so.
How to block automatic updates and prompts on non-jailbroken Apple TV 4 and 4K