Forza Horizon 4

There are two downloadable content expansions for the game.[6] The first of these, Fortune Island, was released in December 2018. It includes a new map, a range of additional cars and adds extreme weather conditions to the game, along with a treasure hunting campaign in which players find treasure chests to earn up to ten million Credits. The second, Lego Speed Champions, was announced at E3 2019 and released on 13 June 2019.[16][17][18] Similar to the Forza Horizon 3: Hot Wheels expansion, it is based on the Lego brand's Lego Speed Champions toyline featuring Lego toy versions of real cars, a map "built" with various Lego pieces, and its own separate campaign.[16][17] It also added a new in-game radio station, Radio Awesome, which is dedicated solely to playing The Lego Movie theme song "Everything Is Awesome" by Tegan and Sara featuring The Lonely Island.[18]

The Series 5 update in January introduced the Free DLC Mitsubishi Motors Car Pack. It included 7 new cars and added a new 10-mission campaign called Isha’s Taxis.[19]

Three car packs have also been released as of 9 April 2019, one including cars from the James Bond films, the other being a collection of Formula Drift cars and another pack of cars from the Barrett-Jackson Car Pack from Forza Motorsport 7.[20]

Every four weeks, at the end of every Spring season, a new update for the game is released introducing new gameplay content, cars, and cosmetic items. The first of these updates, at the end of October 2018, saw the addition of the Route Creator tool and a new Horizon Story, British Racing Green.

The Series 7 update in March 2019 introduced the Festival Playlist.[21] Players complete daily, weekly, and monthly challenges, including, but not limited to, Seasonal Championships, Playground Games, Ranked Adventure, and Seasonal PR Stunts. While completing these tasks alone earns players rewards, they also contribute to weekly and monthly rewards. 50% and 80% completion of both the Series and the current season rewards drivers with an exclusive car or cosmetic item, usually of the Epic or Legendary rarity. The Festival Playlist has continued to be a part of each series since its introduction.

With the Series 9 update in May 2019, the developers implemented a system to prevent wallriding—the practice of driving into a curved wall on the outside of a corner instead of braking and steering, thus allowing the player to carry more speed through a corner—and high-speed collisions in online multiplayer. The system predicts the occurrence of a collision between two cars with a large difference in speed and ghosts the faster vehicle, preventing rammings (both intentional and accidental). The anti-wall riding measures include slowing down a car in contact with the wall for an extended period of time, depending on speed and the predicted distance the player would have travelled if they did not hit the wall.[22]

In July 2019, as part of the Series 11 update, a special Horizon Story was added in collaboration with BBC's Top Gear. The missions, narrated by presenter Chris Harris, provided players with rewards including the "Track-tor" (a race-modified tractor featured in Series 25 of the show) and the Mercedes-Benz G63 AMG 6x6. The update also saw the return of class-based Rivals modes from previous games in the series, and the ability to track progress in the Horizon Life menu, as well as several new unlockable cars in the game's Festival Playlist feature.[23]

In December 2019, as part of the Series 17 update, a new 72-player battle royale-style mode called The Eliminator was added to the game.[24] In this mode, players start by driving around the game world in a fairly slow, weak car such as a 1965 Mini Cooper.[24] As players roam the safe zone, they can acquire car drops that contain more powerful vehicles that randomly appear on the map.[24] Players can also challenge other players to head-to-head races to specific points on the map by pointing their camera at the other's vehicle and honking their horn.[24] Players are eliminated from the event if they drive out of the safe zone (which shrinks over time like in other battle royale games) or lose a head-to-head race, where the winner of such has the option to drive the opponent's car or receive an upgrade.[24] Eventually, when the safe zone shrinks to a certain point, the remaining players will then race to one final point on the map to determine the winner.[24]

In April 2020, as part of the Series 21 update, Horizon Promo, a feature previously found in Forza Horizon 2 and 3 where players take in-game photographs of cars using Photo Mode for rewards, made its return to the Forza Horizon series in Horizon 4.[25]