https://wccftech.com/forza-horizon-5-series-9-update-notes/

The previously announced Forza Horizon 5 Series 9 update has been rolled out on Xbox, Steam, and Windows. We've got you covered with the full release notes.

As covered earlier this week, this new patch for Horizon 5 adds the long-requested Temporal Antialiasing (TAA) support for PC players. In addition, this update allows players to play the game's Stories mode in Co-op with up to six players. Also introduced with the Series 9 update, are the new Hot-wheels-themed cars and cosmetics, a new "Forza EV" monthly rivals event, a duplicate filter to the Car Select screen filter, and various game fixes.