E3 saw the reveal of an October release date for Age of Empires IV, but its much beloved predecessor is not being left behind. Age of Empires II Definitive Edition has begun public testing of its co-op campaign missions via the Public Update Preview on Steam.
To start with, the PUP will include several Historical Battles for testing co-op mechanics. The announcement on Steam also has a rundown of what full-length campaigns will be playable in co-op when the feature fully launches. It amounts to one campaign from each of the game’s myriad expansions (excepting the recent Lords of the West and upcoming Dawn of the Dukes), from the base game’s Saladin campaign up to Tamerlane from The Last Khans. Including the Historical Battles, it adds up to nearly 40 missions.
We don’t have a release date for the full co-op update yet, but the Dawn of the Dukes expansion is scheduled for an August release, and it seems likely the developers would want to pair co-op’s launch with that of the expansion. There’s always the hope for an earlier release, though.