It’s been a long time coming, with multiple delays along the way, but today 343 Industries confirmed that Halo Infinite campaign co-op flighting (their name for beta testing) will kick off in July. Co-op will allow up to four players to team either locally or online, with everyone controlling Master Chief clones. There won’t be full freedom to explore the game’s semi-open world, players can only separate by up to 1000 feet, but on a positive note, full crossplay is supported and campaign progress will be shared between everyone. How exactly will the sharing of progress work? 343’s John Mulkey and Isaac Bender spelled it out…

　　Mulkey: The goal going in was to “allow everyone to play their campaigns together.” This meant that all progress made in the game, regardless of it being through Solo or Co-Op play, would be retained. I could be playing Solo campaign, jump into a Co-Op session for a few hours, then launch back into Solo play and all the mission progress, acquired collectibles, equipment found, achievements earned, and upgrades made in either session would be intact. Gone are the days of playing someone else's game while earning no progress.

　　The way we are handling this is through something we internally refer to as “No Spartan Left Behind”. When players join the Fireteam and choose their save slots to play on, the game aggregates the states of all missions across those saves and sets up a world state in which any missions completed by all Fireteam members are marked as complete while any missions not completed by all are marked as incomplete.

　　Bender: You can think of this system as creating a version of the world that’s like the “lowest common denominator” (or “intersection,” if you’re into set theory) of everyone’s Campaign progress. This way, no matter what you do, no one is completing missions out of order.

　　What this means is that any unlocks you find in Co-Op are retained in single-player. So, if you’re having a really hard time collecting a Skull, you can get in a game with a friend, and if they collect it while you’re in that session, you’ll get it too!

　　In addition to co-op, the ability to replay Halo Infinite campaign missions on the difficulty level of your choosing is also on the way.

　　If you’d like to participate in Halo Infinite co-op flighting, just sign up for the Halo Insider program, then either download the Xbox Insider app if you're playing on Xbox or wait for an email if you’re playing on PC. Be forewarned though, the progress you make during flighting won’t carry over when the feature goes wide.

　　Halo Infinite can be played on PC, Xbox One, and Xbox Series X/S. Co-op flighting begins on July 15. Per the latest Halo Infinite roadmap, co-op should roll out to everyone in late August.