After a quick Google, I found a few articles. To sum up. If you run anything higher than iOS 10.0, you're fine. If you run anything lower than iOS 10, you should upgrade. iPhone X is running iOS 11, so it will have all the latest security updates.
This is a good example why you always need to update to the latest iOS version. Yes, it is okay to wait a few days and see if there are any bugs. There are updates for a reason. You do not always see any change. But boy a lot happens under the hood.
Apple fans will be delighted to hear that the current
versions of its software are not vulnerable. That means anything more
recent than iOS 9.3.5 or, for Apple TV users, version 7.2.2 of the
software for that device. iOS 10 is definitely OK, Armis said.
Any iPhones running iOS 10 are immune to the attack
Apple mitigated the flaw in iOS 10, but all iPhones, iPads, and iPod
touch devices with iOS 9.3.5 or lower, and Apple TV devices with
version 7.2.2 or lower are at risk.