This can now run unsigned code on all iPhones from 4S up to the iPhone X with a Boot ROM Exploit
Boot ROM which is called “SecureROM” by Apple, is the first significant code that runs on an iDevice. The bootrom is read only, so finding the exploits in the bootrom level means that Apple won’t be able to fix it without a hardware revision.
Even though axi0mX had not released a jailbreak today, he has released the exploit to allow developers to use it and create a tethered jailbreak tool.
So could mean that it will lead to, permanently jailbroken devices, dual booting multiple versions of iOS, be able to run Android or other mobile device OSs, and possibly data recovery from disabled devices.