It is based on Bullet Physics.  Most existing cloth items should work.  I won't say all because there probably is one or two items that won't work.  The nice thing I like about this version vs. the old cloth room is that I can paint constraints on every part and control how it interacts.  It will take a bit of time to get used to the new controls and how to paint, but it should be worth it.  You should go look up Bullet Physics for Poser and watch the videos as it like that but taken to a higher level.  Since I have never been able to get a figure to drop through the floor at least not on a version that has been released to the public that problem should be fixed.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13, 14