It only seems like it took forever to get this update out, but at 2 am Pacific Time this morning, the update patch went live according to a post on the official forums. No patch notes or developer comments were made puiblic yet, as a Dev blog post should be going live tomorrow explaining the update.

The patch finally fixes the ever frustrating 4 player co-op lag that was taken to the next extreme that it was so bad. Also fixed were other issues inside the game as well.

Source