Series 9

Series 9 is the ninth series update for Halo: The Master Chief Collection, and was released on August 31, 2022.

The series is the first to be released under the "Series" nomenclature; all MCC updates released between late 2019 and 2021 were done so under the "Season" structure, though due to issues meeting the original development schedule updates were slowed down and the terminology changed. Early on in the support life cycle of the collection, a Season 9 update was planned for release in 2021, though was ultimately pushed back and cancelled due to issues in development (alongside a hypothetical Season 10). As such, Series 9 contains much of the content developed for The Master Chief Collection originally slated for the Season 10 update. The change in Season terminology has also seen rebranded as Spartan Points.

An update followed Series 9 on July 12, 2023, which introduced Theater mode into Halo 4, along with a slew of additional modding items, such as the ability to load in the rest of the Halo Online maps, alongside older content from early builds of Halo: Combat Evolved

Halo: The Master Chief Collection

 * Various user interface improvements
 * Seasons rebranded as Series
 * rebranded as
 * Moa statues added into Halo: Reach, Halo 3: ODST, Halo: Combat Evolved, Halo 4, and Halo 2 campaigns
 * Post-match Poses added into all Halo games, except for Halo 3: ODST
 * In-game subtitles added into Halo 2 (both Classic and Anniversary), Halo 3, Halo 3: ODST, and Halo: Reach.
 * Bandana and Acrophobia skulls added into Halo: Reach and Halo 4.
 * Acrophobia skull added into Halo: Combat Evolved.
 * Firefight Custom Game Browser for Halo 3: ODST and Halo: Reach
 * Player count for Custom Firefight sessions increased from four players to eight players
 * Join-in-Progress
 * Halo: Combat Evolved and Halo 2 Cut Content available for Steam only

Halo 3

 * Halo 3 Editing Kit
 * Sky bridge, Reactor, and Lockout maps available for Steam only
 * New gamemode: Escalation Slayer
 * Forge content

Halo 2: Anniversary

 * Five new multiplayer Spartan armor sets; 1 canon and 4 Fractures.
 * Breach
 * Bioroid
 * Megaframe
 * Trooper
 * Panzerdoll
 * Forge improvements;
 * Bake lighting function changed from a single button click to a hold option, allowing switching from Monitor from player mode to be less annoying (similarly to the functions of the Forge mode in Halo 5: Guardians).
 * Various bug fixes
 * 20 weapon skins.
 * 4 for the Battle Rifle
 * 4 for the Assault Rifle
 * 4 for the Sniper Rifle
 * 4 for the Shotgun
 * 4 for the Rocket Launcher

Halo: Reach

 * Forge improvements;
 * Object duplication added, in a similar fashion to the feature introduced in Halo 4
 * Reset object orientation hotkey added, similar to the feature introduced in Halo 4
 * Delete by palette/delete everything options added
 * Location name marker options added to Reach forge, similar to the feature introduced in Halo 5: Guardians. 256 names are available to select based on those present across Halo: Reach existing maps, though the feature is only available for use on Forge World and Tempest.
 * Several vehicles have been added to the Forge palette on Tempest.
 * Elites can now pilot the Sabre.
 * Space fighter orientation now appears identically for hosts and non-hosts
 * Various bug fixes
 * Halo: Reach Editing Kit released

Halo 4

 * Forge improvements;
 * Bake lighting single-button press functionally added, the same as Halo 2: Anniversary's noted above.
 * Subtitles for Sangheili dialogues added into Spartan Ops.
 * Theater for Halo 4's campaign and Spartan Ops.
 * Recharge and Survivor Support upgrades and Resistor Tactical package added.
 * Mods support.