원문 게시자: Albert ,
As Apple had stopped signing the firmware, you can no longer downgrade iOS 11.4.1 to iOS 11.4 Beta 1, 2 or 3 on iPhone. If you upgrade to 11.4.1, you will no longer be able to jailbreak your iPhone. It is said that there are some third-party utility can help jailbreak iPhone with iOS 11.4.1, you may research that. Good luck!