Some weapons were nerfed and some were buffed in the latest massive Xbox One and PS 4 patch for "Call of Duty Black Ops 3." The Haymaker 12, BRM light machine gun, Gorgon and L-CAR 9 were among the weapons that got nerfed by either having their range, damage or recoil reduced. On the other hand, the Dingo, KRM-262 and Argus are among those that got slightly buffed.
Besides that, according to the support pages for Treyarch's "Call of Duty Black Ops 3," the massive update in general introduced Barracks in the leaderboards, Cryptokeys in Arena and Public matches after playing consecutive matches in the same playlist, improved team balancing in Arena and Public Matches and fixes to some known user interface errors.
As for "Call of Duty Black Ops 3" on PC, there was an update too and it was around 520 MB. Not only was it unannounced but there were no patch notes posted as well. According to VG 24/7, it was most likely because of the weekend timing but the fixes are quite similar to those for PS4. The PC update brought changes to Spawn locations in Free for All and Gun Game and increased amount of score earned in Search & Destroy among others.
But what is now available across all platforms is "Call of Duty: Black Ops 3's" double XP weekend, where in the player gets to level up weapons XP twice faster. According to Express UK, Treyarch launched the Double XP Weekend event on Thanksgiving Day, Nov. 26 and it will run through Monday Nov. 30. So those too busy carving turkeys can still participate in the event that can help unlock special arsenal items because XPs rise faster.
It should be noted that, unlike the previous double XP event, this one only applies to weapon XP, hence the name.