Team Xbox explain the Xbox Series X Smart Delivery in this video and briefing. For gamers, this means always having the most optimised version (without additional cost) of the game for your consoles even if you upgrade to a new console. Obviously developers can opt-in or not for this feature. One game supporting this is Microsoft’s Halo: Infinite and host of others according to the video.
One of the most exciting of the technologies we’re introducing with Xbox Series X is Smart Delivery, which will ensure that you always play the best version of the games you own for your console, across generations. This technology is available for all developers, and all Xbox Game Studios titles that are Optimized for Xbox Series X, including Halo Infinite, will support Smart Delivery.
It means that if you purchase the Xbox One version of a supported title, we will deliver the best version of it to your Xbox One, as usual. If you decide to jump into the next generation with Xbox Series X, we will automatically provide the Xbox Series X version of the game at no additional cost when it becomes available.