Initially the OpenAccess Free Edition didn't support all the databases the Commercial Edition does. However, in June 2012 we decided to make the entire functionality available in the Free Edition and all the databases are supported there with no limitations.
In case you also require priority support service, in addition we are offering such option for OpenAccess as part of the DevCraft collections
you can purchase from our web site. Otherwise, with the Free Edition, you can only use the community forums as source of information and help.
Let me know if you need any clarifications on the current offerings or you would like to know other details.
the Telerik team
Telerik OpenAccess ORM Meets ASP.NET Web API. Read more.