At E3 today Microsoft made it official, their new console codenamed Scorpion, is set for a launch of Holiday 2017. Microsoft is calling it the most powerful console ever. Sony confirmed just a couple days ago that they would have something about their newest console at E3 too, so I guess the next gen console is now your last gen console.
Now in theory this doesn't mean you have to throw out your Xbox One just yet. They said that all future games would be compatible with the Xbox One, Xbox One S (also just announced) and the new Xbox Scorpio. Essentially this is more of an upgrade to the Xbox One that would allow 4K and VR gaming. In PC terms they're upgrading their video card but not doing a clean install.
It's an interesting strategy, even if it's not the most innovative. From the beginning PC gamers have been mocking the Xbox One and PS4 for low framerates and less than 1080p resolutions. When both consoles launched PC's were just starting to dabble in 4K gaming, the fact that neither produce 60fps at a "lowly" 1080p resolution didn't bode well for their longevity. 4K Televisions aren't that expensive anymore, people are looking for 4K content and if Microsoft and Sony don't provide it someone else will. It's smart that they've revamped their machines to take advantage of it.
The interesting part here will be the backwards compatibility for the Xbox One. How long will developers and consumers want to be handcuffed to the old hardware. This has been one of the complaints over PC gaming for years, by programming for the minimum specs you cut yourself off at the knees when it comes to throwing more bells and whistles into a game. My guess is it will start with special Scorpion editions with more content or textures "optimized for Scorpion". Then exclusive titles or DLC will follow, before you know it they only thing new being released on the Xbox One will be Madden and the new Skylanders game.
Should be interesting stuff, without looking a bunch of stuff up on wikipedia I don't think we've seen a jump in console hardware this drastic this quick.