Hi Martin and Rich,
Thanks for the timely question. We are actually tackling this topic within our team at the moment. There will be a blog post out shortly and the samples will also be updated to show best practices for placing banners and native ads according to Apples design guidelines for the iPhone X.
That said, the short answer is we absolutely recommend adhering to Apples design guidelines and instead of placing banners, etc at the edges of the screen, place them at the edges of the safe area of the screen.
Keep an eye out for additional updates on the iPhone X in the coming weeks,
Best,
Sam