YouTube for iOS has been updated to support iPhone X, making it one of the first Google apps to take advantage of Apple’s Super Retina HD display with 2436×1125 resolution and 19.5:9 aspect ratio.
The update to version 12.43 adds full-screen support for iPhone X, which can be activated using a ‘pinch to zoom’ gesture. When in full-screen mode, mind that notch as you’ll have to deal with loosing the top and bottom of the video. It doesn’t cut out much, however.
YouTube 12.43 for iOS is now available to download from the App Store.