Last update for Forza Horizon 4

Based on the official news for Forza Horizon 4, there will be no new content in future seasons, update 37 is the last one.

"Starting with next month’s Series 38, the seasonal playlist will become a mixtape of rewards, championships, and challenges from previous updates, starting from Series 7 through Series 32. You can expect more chances at some rare cars and rewards that have only come around a few times, and relive some of your favorite seasonal challenges."

Jacob Norwood

The good news is that the support team will still work on Forza Horizon 4, so game is not abandoned yet! But Forza Horizon 5 is coming in November so development will be focused on it.