I wanted to give everybody a heads up about this since it seems pretty important. I don't have an iPhoneX so I can't test if the construct engine already deals with this problem automatically.
I just found out that AdMob has a very close in time deadline for banner positioning on iPhoneX. ("Please review these policy updates and our suggested implementation guide to ensure you're compliant by November 20th.") Banner ads need to be positioned in the safe area on iPhoneX - otherwise you'll be violating AdMob's policies and might suffer the consequences.
You can find the corresponding blog post here.