Update: iOS 11.2.6 is now unsigned. You can no longer use futurerestore to restore any device to any firmware below iOS 11.3. Do not attempt the restores mentioned in this article.
With the official release of iOS 11.3, the clock is ticking on iOS 11.2.6 signing. Normally this wouldn't mean much to jailbreakers, who would be staying on a lower jailbroken firmware. This time however, it's different. Many users on iOS 9 and 10 jailbreaks are waiting to see how the iOS 11 tools turn out before making the jump. So far, iOS 11.2-11.2.6 have maintained SEP and baseband compatibility with iOS 11.0-11.1.2 (the last jailbreakable firmwares), which allowed users to make the jump at any point, or wait it out a little longer.