For those upgrading to the 3.0 RTM, please check out this video. I've been upgrading my demo solution to check out the impact and so far all I've really had to do is name my endpoints and remove some config per the video. Thus far I've gotten my version of Full Duplex working along with basic Pub/Sub. Next I'll be hitting the Distributor since we use that pretty heavily. I'll be sure to post back any gotchas that I find.