Keen Lab developers successfully jailbroken iOS 11.3.1 and install Cydia. Latest iPhone X is running iOS 11.3.1 device jailbroken via this Keen Lab jailbreak method.
Keen iOS 11.3.1 jailbreak support devices
iPhone X, iPhone 8 Plus, iPhone 8, iPhone 7 Plus, iPhone 7, iPhone 6S Plus, iPhone 6S, iPhone 6 Plus, iPhone 6, iPhone SE, iPhone 5S.
iPad Pro (10.5-inch), iPad Pro (12.9-inch), iPad (9.7-inch), iPad Mini 4, iPad Air 2, iPad Mini 3, iPad Pro (9.7-inch), iPad Pro (12.9-inch)
iPod Touch 6
How to use Keen tool for iOS 11.3.1 jailbreak
Keen iOS 11.3.1 jailbreak IPA still not released for public. Please check back soon Keen labs.com official site for download Keen IPA.
Download Cydia Impactor
Connect your device to PC
Drag and drop Keen IPA to Cydia Impactor
Enter Apple ID
Wait for a complete message
Now visit device Home page and find Keen App.
Tap Jailbreak button to start the process and Download Cydia.