343 Industries planned to kick off the first Insider test of Halo 4 last weekend but was pushed back at the last minute. In a surprise opening and without waiting for the next weekend, the developer has now kicked off the highly-anticipated flight. If previous plans hold true, everyone who has signed up to be a Halo Insider will receive an invite this time, meaning both PC (across Steam and Microsoft Store) and Xbox One users are eligible.

According to 343 Industries community manager John Junyshek, the invites are still going out in waves, so keep an eye out for an email with instructions or head to HaloWaypoint and check for notifications there.

From Halo 4, this flight contains Requiem, Forerunner, Reclaimer, Shutdown, and Composer campaign missions, 11 multiplayer maps across Social and Competitive playlists, and Spartan Ops content, among other enhancements such as Forge improvements, advanced graphics options, and an FOV slider.

Aside from those, 343 Industries is finally preparing to bring cross-play across PC and Xbox One versions as well as input-based matchmaking and server region selection capabilities to the Master Chief Collection. The testing of these features is also happening in this build.

In other Halo news, it was announced earlier today that Halo: The Master Chief Collection will be receiving Xbox Series X|S enhancements on November 17, bringing many enhancements that have been made to the new PC version over to the next-gen console version.