Just before you gets excited - this is not the big update that Treyarch and Activision promised later in the week but there's plenty of changes to satisfy Call of Duty: Black Ops 4 fans, such as upping Duos player count in Blackout.
Along with Blackout's Duos player increase comes the Quads decrease from a maximum of 100 to 88. This should theoretically make things a bit less hectic when playing Quads, although we should know soon enough.
Treyarch also pointed out that playlist tiles for Call of Duty: Black Ops 4's multiplayer and Blackout were changed as part of the regular rotation, more on which will be revealed soon. For now, the company said that the TDM playlist supports parties of six and that the featured playlist was changed to Heist.
It seems that the recent balance pass on Call of Duty: Black Ops 4's Zombies mode, which included tweaking hellhounds' spawn radius, speed and frequency, resulted in peculiar artefacts, for the lack of a better word. Treyarch wrote that they've addressed the issue where hellhounds exhibited "some very...un-doglike behavior".
Having launched only recently, there's plenty of work left on Call of Duty: Black Ops 4 and judging by the frequency of issues, Beenox will have their work cut out for them. However, the company insists that the new CoD is no mere port, as evidenced by the weapon knockback and general handling.
There's a specific issue that is plaguing PC users, which is crashing when pairing up weapon camo and fast lock attachment on the Hellion Salvo launcher. So, until they've got a proper solution, Treyarch and Beenox advised players to steer clear of this PC-crashing combo. Apparently, this issue will be fixed in the next update.
Call of Duty: Black Ops 4's PC players have also reported strange CPU usage scenarios, where the game would stutter and hit 100 per cent usage. Some users had luck with tweaking its config files, specifically the line that reads "Thread count for handling the job queue worker_threads", which you should set to the number of threads at your disposal minus one.
Note that players have had mixed results with this solution but since the worst case scenario is leaving things as they are - it's well worth the shot.
You can find Call of Duty: Black Ops 4's patch notes here.