WebORB for PHP update (Flex Data Services for PHP)

Some really cool stuff is happening around WebORB for PHP. The product is going to be a direct port from WebORB for .NET and thus far we already have basic remoting working. The product is going to be free and open source for the most part (that includes support for Flash Remoting/AMF0, Flex RPC/AMF3, custom serializers, client/server type mapping, security, etc). The commercial part will include support for Flex Data Management Services and a few other cool things we're working on.
One of the goals I have set for the product is the ease-of-use. Starting from installation and deployment of the user application classes to management and configuration of the product, I want the developers to have a very pleasant and enjoyable experience. The deployment model should be as simple as dropping a PHP class into the designated folder and it will automatically be available to all supported clients (Flash and Flex for now). If you want to secure it - no problem, open management console and set your security restrictions.
I hope to have a preview version of the product by the end of this month. One thing that's not entirely clear is the licensing enforcement for the commercial part of the product. I wonder if there is a precedent in the PHP world for a free, open-source product that has a commercial upgrade path. If you know of anything like that, please submit in the comments.