[UPDATE] The Warzone Firefight update is now live. 343 has also released a new trailer.

The original story is below.

Halo 5‘s Warzone Firefight expansion arrives today. It’s the largest and most substantial update to the Xbox One shooter to date, introducing new modes, maps, weapons, and more. The other big piece of Halo 5 news is that, as of today, the game is completely free for all Xbox Live Gold members as part of a Free Play Days promotion. You can download and play the game as much as you want until July 5, at which time it will return to the normal price.

The expansion is slated to be released sometime in the morning PST, so it might still be a few hours before it arrives. We’ll update this post when the add-on officially lands, at which time we should know about the file size and some other particulars.

Warzone Firefight is named after the new mode of the same name that is one of the key additions to Halo 5 with the update. Developer 343 previously tested this mode back in April as part of an open beta. We also recently learned that there will be a new grunt-mech boss named Grunt Goblin.

There are also three new multiplayer maps included with Warzone Firefight, including two for Warzone (Attack on Sanctum and Prospect) and one for Arena (Molten). As for the new Reqs, these include the Cinder and Cyclops armor sets, as well as new Covenant vehicle and weapon variants, among others.

It’s not just Halo 5’s multiplayer that’s getting new content with the Warzone Firefight expansion. 343 is bringing a Score Attack mode to campaign, while a new Forge canvas, Tidal, will be available for the map-making tools.

Check out the image below to see everything included with Warzone Firefight.

Halo 5’s other expansions included The Battle of Shadow and Light (November), Cartographer’s Gift (December), Infinity’s Armor (January), Hammer Storm (February), Ghosts of Meridian (April), Memories of Reach (May), and Hog Wild (May).

Microsoft has said Halo 5’s free expansions will end in June 2016, meaning Warzone Firefight is likely the last one.