As most of you probably already know, as you are experiencing it on your consoles, the April update for Xbox has made it's way into our hard drives.
One of the big ones is that now the Xbox One X and Xbox One S support an output of 1440p resolution for games and media. There are plenty of other updates to Video and Display, streaming, capturing, and the list goes on your best bet is to check out this link that will give you both videos and words to walk you through everything new on Xbox Live. Mainly because Major Nelson's got you covered and he does a much better job here then i could ever do. Check out everything updated here:
April Update via Major Nelson