A new update for Halo: The Master Chief Collection has added "experimental" cross-platform co-op for both Halo 3 and Halo 3: ODST.
The feature will let anyone on PC, Xbox One or Xbox Series X/S play these games' campaigns co-operatively online together.
In patch notes, developer 343 Industries said the cross-play had been tested internally - though the company now needed "additional insight from real players with different networking setups". If you experience issues, you're encouraged to report them so 343 can improve the feature further.
Other changes included in the patch include improvements to ODST Firefight and Floodfight, Custom Game Browser tweaks including a new Quick Match option, fresh skulls for Halo 2, 3 and ODST, new medals in Halo 3, mod tools for ODST, and dozens more general bug fixes.
It's a little surprising to see 343 going to the effort of adding campaign co-op to Halo 3 and ODST now - but perhaps this is a precursor to work for Infinite?
Halo Infinite's second season, Lone Wolves, is set to arrive on 3rd May and will contain new maps, modes, themed limited-time events, and a fresh Battle Pass.
It won't, however, contain Infinite's long-awaited campaign co-op and Forge modes.
Recently, 343 community director Brian Jarrard said the studio understood some fans were "simply out of patience" with the game's various frustrations, and that his team was "certainly not happy to be unable to meet player and community expectations".