Update: Xbox Series X backwards compatibility will go both ways, at least for the early years of the new console. Xbox Game Studios head Matt Booty confirmed Microsoft's commitment to making all new Xbox games playable within its current family of devices in a new interview. That means no console launch exclusives, at least not in the traditional sense.
"As our content comes out over the next year, two years, all of our games, sort of like PC, will play up and down that family of devices," Booty told MCV. "We want to make sure that if someone invests in Xbox between now and [Series X] that they feel that they made a good investment and that we’re committed to them with content."
Booty said it's still important that Halo will be "there at the launch of the console, taking advantage of all the features". So even if you play through Halo Infinite on Xbox One first, you'll still have something to look forward to if you play it on an Xbox Series X later.
Update: Both Phil Spencer and Xbox partner director of program management Jason Ronald expanded upon the Xbox Series X backwards compatibility in an interview with GameSpot.
"We wanted to make sure we had that, day one, we could deliver on the compatibility promise, and so I've been playing quite a few [Xbox 360] games on my [Xbox Series X] and Xbox One games on the [Xbox Series X] and that's just to ensure that we can be there day one," Phil Spencer said.
"We have thousands of games that run on Xbox One today," Xbox partner director of program management Jason Ronald told GameSpot. "We want those games to be able to come forward with you but we also want your services to come with you. We want your gaming legacy to come with you, whether that's your Gamerscore, whether that's your friends list, all your Achievements, your game saves, all of that should come forward so there are no barriers for you as you think about moving forward."
But making the Xbox Series X backwards compatible is no easy feat. It was such a difficult process in the past, Spencer points out that Microsoft "paused [their] backwards compatibility program for [Xbox 360] on Xbox One." The differences in hardware pose the biggest problem even with making the newer Xbox One games playable on the next-gen console."One of the biggest challenges is console games are usually hyper-optimized to the unique hardware capabilities of the device, and this is a new generation of hardware," Ronald says. "It is a new chip architecture. At the same time, we did design the silicon with [backwards] compatibility in mind, so we did make certain decisions to try to lessen that work, but I don't want to trivialize how much work the team's actually doing because there is a tremendous amount of work."
Original Story: The process of ensuring three previous console generations of games all play on Xbox Series X has been a lot of work. "There is work in ensuring [backwards] compatibility across those generations," Spencer said. "So, as you might remember, we slowed down and paused our backwards compatibility program for [Xbox 360] on Xbox One."
"[It takes a lot of work] even for Xbox One games, because one of the biggest challenges is console games are usually hyper-optimized to the unique hardware capabilities of the device, and this is a new generation of hardware," Ronald added. "It is a new chip architecture. At the same time, we did design the silicon with [backwards] compatibility in mind, so we did make certain decisions to try to lessen that work, but I don't want to trivialize how much work the team's actually doing because there is a tremendous amount of work."
Unless you were watching the Xbox E3 2019 press conference very carefully, you might have missed just how awesome the Xbox Series X backwards compatibility will be. Microsoft announced that Xbox Series X will arrive at the end of 2020, but it also teased just how far back its support for backwards compatibility will reach.
Microsoft stated in its conference that Xbox Project Scarlett will support games from all four generations of Xbox consoles, which means original Xbox, Xbox 360, and Xbox One games as well as next-gen games.
In a behind-closed-doors meeting at E3 2019, Microsoft's Dan McCulloch confirmed this to GamesRadar:
"All of your current games will be forward compatible to play on Scarlett, and will look the best on Scarlett," explained McCulloch.
That means that all Xbox One games, plus all the Xbox 360 and original Xbox games currently available via Xbox One backwards compatibility, will also be playable on Xbox Project Scarlett. We've already seen how the Xbox One backwards compatibility tech can liven up old games with smoother visuals, and given the Xbox Series X specs, it should be able to ramp that up even further. You can only do so much to old games, obviously, but the implications for Xbox One games are tantalizing.
In any case, Xbox Project Scarlett backwards compatibility should make for quite the gaming library when it launches in 2020, so prepare yourself for some serious gaming sessions.
But wait, there's more. Microsoft has also confirmed that your Xbox One peripherals will work with Xbox Series X too, and the new Xbox Series X controller will be backwards compatible with the Xbox One X family of consoles too. No specific word on Kinect yet, but we can but hope.
Want more Xbox goodness? Why not check out our pick of the best upcoming Xbox One games to bridge the gap before Project Scarlett launches next year?