As Jay written in his M4 announce:
This is the time when open source projects like RichFaces really need the help of their communities. In order to get 4.0.0.Final stabilized and ready to go for everyone we need everyone to take these later milestone releases for a spin. We've already had some great feedback from users on Milestone 3, and earlier and really want to keep this going. Believe us, this type of feedback makes all the difference!!!
So now we want to quickly check which part of our great and large community tried RF 4 Milestones in their applications. Please, spend a minute to answer that poll to provide quick and useful feedback to us. And for those who want to share any details: we created special topic for that and any comments and concerns there will be highly appreciated!