Here's how to downgrade iOS 11 / 11.2.1 to iOS 11.1.2 / 11.0.3 / 10.3.3 (on 6s only) on a compatible iPhone, iPad, or iPod touch device.
You can still downgrade from iOS 11.1.1 to iOS 10.3.3 on your iPhone 6s, as apple continues to sign the firmware. Here are the details.
You can now download iOS 11.1.1 IPSW links and over-the-air (OTA) update featuring various bug fixes for iPhone and iPad users.
iOS 11.1.1 jailbreak on iPhone X has been demoed on stage at POC2017 by KeenLab. Here are the details on it.