Using this tool will restore the RootFS to its stock state and reset the user data. So creating a backup using iTunes before using it is recommended. It supports all devices running iOS 11.3 to 11.4 Beta 3. The 11.2 to 11.2.6 support will be coming really soon. The 11.0 to 11.1.2 support will also be added in the near future. Although there's an option to not perform a full restore and keep the user data, I would really not recommend it, since it will leave a lot of left-overs from your jailbreak. Follow me at @Pwn20wnd for future updates about this tool or to troubleshoot any unexpected behavior that you may be having with this tool.