Microsoft did indeed officially unveil its new Xbox today, with Project Scorpio coming to market as the Xbox One X. With major enhancements in performance capability targeting an exlusively 4K gaming experience.
The new Xbox retains backward compatibility with the current Xbox One and One S, as well as supporting the existing Xbox 360 backwards compatibility program. That extends to Xbox One accessories as well, so an upgrade for existing users will be relatively painless.
Not sure how much value this adds but Microsoft intends to introduce the capability to run original Xbox titles through a new compatibility program. I guess that's a bonus if you have older Xbox games which you'd still like to play, however it seems very niche to me...
The new console will hit the sales floor in Novemeber, with a launch price of $499. That's pretty steep, although I'd expect most buyers to be trading up from an existing Xbox One, which should offset the pain somewhat.