Every significant new device is accompanied by significant updates to the HIG and the iPhone X is no exception. However, I can sum this up concisely by simply asking if you paid good attention to the safe area changes earlier this year? If you did, you're most of the way there.
David Smith digs into the changes to watch apps which will be possible with the addition of LTE in the series 3 devices. I'm still very much of the opinion that the watch is always going to be a limited platform for apps, but having ubiquitous data certainly opens up a few new possibilities.
It's been a while since we had any articles about hybrid iOS apps, so this article by Zach Waugh is a nice update of how Basecamp have continued to use this technique. It's an in depth article, and for this kind of app it makes a lot of sense.