Sadly, Blizzard didn’t announce Diablo 4 at BlizzCon, but it did reveal that the original Diablo will be recreated in Diablo III via an anniversary patch.
Update 2.4.3 will introduce a new annual event called the Darkening of Tristram which takes players back to the first time evil invaded Sanctuary.
“Head to Old Tristram in Adventure Mode during the month of January to discover a portal where you can explore a Diablo III recreation of the events that transpired in the original Diablo,” the developer writes. “Filled with iconic enemies, familiar faces, and some old-school items, this event is a nostalgia-packed adventure down memory lane. Transmogrification rewards, achievements, and a few extra surprises await those brave enough to plumb the depths below Tristram.”
The new dungeon is 16 levels deep and features the four main bosses from the first Diablo, the original music, and a new “Retrovision” graphics filter that makes the game look like the original and locks players to old-school eight-directional movement.
Update 2.4.3 will be added to the PTR this week and will officially launch in January 2017.