Update 66, also known as Series 66, was released for Forza Horizon 4 on September 21, 2023.
Festival Playlist[]
- See also Festival Playlist & Forzathon
Series[]
- Duration - September 21, 2023 at 2:30 pm (UTC) to October 19, 2023 at 2:30 pm (UTC)
- Series Completion Bonuses
- 1x
Horizon Backstage Pass - 50% unlock 
Rare 1995 BMW 850CSi (Hard-to-Find Car) - 80% completion
- 1x
Summer Season[]
- Main article: Forza Horizon 4/Update 66/Summer Season
- Duration - September 21, 2023 at 2:30 pm (UTC) to September 28, 2023 at 2:30 pm (UTC)
- Season Completion Bonuses
Legendary 2020 Jeep Gladiator Rubicon (Hard-to-Find Car) - 50% unlock- Legendary 2007 Peugeot 207 Super 2000 (Hard-to-Find Car) - 80% unlock
- Event Rewards
- Legendary 1989 Ferrari F40 Competizione (Autoshow Car) - "The Most Iconic Trio" Trial
- Legendary 2016 Lamborghini Centenario LP 770-4 (Autoshow Car) - "Summer Games" Playground Games
- Legendary 1987 Ferrari F40 (Autoshow Car) - "Is This The Way To Castelletto?" Championship
- Forza 1969 Chevrolet Nova Super Sport 396 Forza Edition (Wheelspin Car) - "Battle Of The Brands" Championship
- Legendary Modern Race Suit Red (Outfit) - "Marathon Runners" Championship
- Forzathon Shop
- Epic 1974 Hoonigan Ford Bronco (Hard-to-Find Car) - 599 FP
- Legendary RTR Fun Haver White (Tops) - 250 FP
- Epic Golden Leather Jacket (Jackets) - 250 FP
- Epic 1985 Toyota Sprinter Trueno GT Apex (Hard-to-Find Car) - 599 FP
Autumn Season[]
- Main article: Forza Horizon 4/Update 66/Autumn Season
- Duration - September 28, 2023 at 2:30 pm (UTC) to October 5, 2023 at 2:30 pm (UTC)
- Season Completion Bonuses
- Epic 1968 Pontiac Firebird (Hard-to-Find Car) - 50% unlock
- Legendary 2019 Bugatti Divo (Hard-to-Find Car) - 80% unlock
- Event Rewards
- Legendary 2019 Rimac Concept Two (Hard-to-Find Car) - "The Holy Trinity" Trial
- Legendary 1986 Hoonigan Ford RS200 Evolution (Hard-to-Find Car) - "Autumn Games" Playground Games
- Rare 2009 Vauxhall Corsa VXR (Hard-to-Find Car) - "Old Habits Die Hard" Championship
- Forza 1972 Ford Falcon XA GT-HO Forza Edition (Wheelspin Car) - "Special Performance" Championship
- Legendary 1996 Ferrari F50 GT (Autoshow Car) - "Supercar Showdown" Championship
- Forzathon Shop
- 2009 Mercedes-Benz SL 65 AMG Black Series Forza Edition (Car Mastery Perk Reward Car) - 599 FP
- Rare Autumn Mittens (Hands) - 250 FP
- Epic Golden Leather Jacket (Jackets) - 250 FP
- Legendary 1969 Toyota 2000GT (Hard-to-Find Car) - 599 FP
Winter Season[]
- Main article: Forza Horizon 4/Update 66/Winter Season
- Duration - October 5, 2023 at 2:30 pm (UTC) to October 12, 2023 at 2:30 pm (UTC)
- Season Completion Bonuses
- 1x Horizon Backstage Pass - 50% unlock
- Legendary 2006 Koenigsegg CCX (Hard-to-Find Car) - 80% unlock
- 1x
- Event Rewards
- Rare All About Me (Emote) - "The Triumvirate" Trial
- Legendary 2018 MINI X-Raid John Cooper Works Buggy (Hard-to-Find Car) - "Winter Games" Playground Games
- Epic 2010 Audi TT RS Coupé (Wheelspin Car) - "Getting Cold Street" Championship
- Epic 2010 BMW M3 GTS (Hard-to-Find Car) - "Power Struggle" Championship
- Epic 1967 Volkswagen Type 3 1600 L (Hard-to-Find Car) - "Magic Number" Championship
- Forzathon Shop
- Epic 2019 McLaren 720S Spider (Hard-to-Find Car) - 599 FP
- Epic Golden Skirt (Legs) - 250 FP
- Legendary RTR Born to Fun White (Tops) - 250 FP
- Rare 1984 Rover SD1 Vitesse (Hard-to-Find Car) - 599 FP
Spring Season[]
- Main article: Forza Horizon 4/Update 66/Spring Season
- Duration - October 12, 2023 at 2:30 pm (UTC) to October 19, 2023 at 2:30 pm (UTC)
- Season Completion Bonuses
- 1x Horizon Backstage Pass - 50% unlock
- Legendary Patrol Outfit (Outfit) - 80% unlock
- 1x
- Event Rewards
- Legendary 1966 Porsche 906 Carrera 6 (Hard-to-Find Car) - "The Triple Threat" Trial
- Legendary 2018 MINI John Cooper Works Countryman All4 (Hard-to-Find Car) - "Spring Games" Playground Games
- Epic 2018 Ford Mustang RTR Spec 5 (Hard-to-Find Car) - "Mustang vs. Mustang" Championship
- Legendary 1967 Chevrolet Chevelle Super Sport 396 (Hard-to-Find Car) - "Muscle vs. Import" Championship
- Forza 1988 BMW M5 Forza Edition (Wheelspin Car) - "Touring Masters" Championship
- Forzathon Shop
- Rare 1992 Toyota Supra 2.0 GT (Hard-to-Find Car) - 599 FP
- Rare Spring Sweater (Tops) - 250 FP
- Legendary Sapphire Crown (Hats) - 250 FP
- Epic 2017 Aston Martin Vulcan AMR Pro (Hard-to-Find Car) - 599 FP
