https://motherboard.vice.com/en_us/article/gy39b4/only-piracy-can-save-forza-horizon-2-now

Monday, Microsoft Studios announced it would stop selling Forza Horizon 2 on Xbox One via its digital store starting on September 30. If you’ve ever wanted to play the game, you’ve got a little more than a month to download your own copy. As long as you’ve purchased the game, Microsoft says you’ll be able to download it in the future. But no one can buy it ever again, at least not from the Xbox Store. Microsoft aptly calls this an "end of life" status.

Microsoft is giving away the DLC for free, has put the game up as part of its subscription service (meaning subscribers can grab for no extra charge), and given the community advanced warning. That’s all great, but it’s cold comfort for anyone new who wants to buy the game after October 1. Forza Horizon 4 comes out the day after Microsoft plans to pull Forza Horizon 2 from its store. Similarly, in 2016, Microsoft stopped selling the original Forza Horizon right before the release of Forza Horizon 3. We asked Microsoft if it had any plans to make Forza Horizon 2 available to purchase by other means in the future, and it referred it us back to its original announcement.