Series 5: Anvil

Season 5: Anvil is an upcoming season for Halo: The Master Chief Collection, expected to be released on January 27, 2021. 343 Industries intends to release the previously-cut AKIS and Mariner helmets as part of this update, after they were pushed back from Season 4 due to difficulties encountered during development. Additionally, Season 5 sees the introduction of 12 armor sets from the cancelled game Halo Online into Halo 3.

Season unlocks
Season 5 is expected to add the following content to the game. Notably, the Halo: Reach and Halo 3 customization options were implemented into the game in the Season 4 December update, as available for preview in the game's menus. However, they are unable to be unlocked and used in-game without the use of modding.

Halo: Reach

 * 2 new Halo: Reach helmets: AKIS, Mariner
 * 3 Halo: Reach helmet attachments for AKIS: GRD, CBRN, GRD/CBRN
 * 3 Halo: Reach helmet attachments for Mariner: Mister Chief, Defiant and OPTREX
 * Six new Halo: Reach chest armors, five of which are new robot arm variants of existing chests and one new:
 * Default [R]
 * UA/Counterassault [R]
 * Tactical/Recon [R]
 * Tactical/Patrol [R]
 * Collar/Grenadier [UA] [R]
 * EXO/TSCS

Halo 3
For Halo 3, the existing "New Skins in Halo 3" toggle will be updated to include the new armor permutations mentioned below alongside weapon and vehicle skins. If the new cosmetics are turned off, any players using Halo Online-based armor will instead display as using the default Mark VI.


 * Techsuit customization for Halo 3
 * Two new techsuit options for Halo 3 (GEN2 and GEN2 Tinted)
 * The game's original GEN1 techsuit has been replaced with an updated, slimmer techsuit based on the Halo 2: Anniversary design for compatibility with the new armour
 * Forearm and leg armor customization for Halo 3
 * Twelve new armor permutations for Halo 3, originally from Halo Online:
 * Air Assault
 * Aviator
 * Compass
 * Deadeye
 * Demo
 * Hivemind
 * Navigator
 * Pioneer
 * Soldier
 * Suture
 * Tanker
 * Warrior


 * 26 new weapon skins and 1 new vehicle skin for Halo 3
 * 8 for the BR55HB battle rifle
 * 2 for the SRS99D-S2 AM sniper rifle
 * 1 for the M41 SPNKR
 * 2 for the MA5C assault rifle
 * 2 for the M6G magnum
 * 3 for the M7 SMG
 * 1 for the Type-33 fuel rod gun
 * 1 for the Type-33 needler
 * 1 for the Type-25 plasma pistol
 * 1 for the Type-25 plasma rifle
 * 3 for the Type-51 carbine
 * 1 for the M274 Mongoose