This update is to release new levels for the weekend, these will be added to the current pool, expanding it. This is partly because we are not able to ship out as many new maps as we would like this week, along with being a shorter holiday week, one of our level designers is out this week so we're shipping about half as many new maps as we normally expect.
You may notice the "godray" effect has returned on the killhouses, but other than that there should be no other "gameplay" changes with this update when compared to the hotfix that was completed yesterday.