ODA Viewer and ODA File Converter are example projects that illustrate the possibilities of the ODA framework. They are free downloads that you can use to get an overview of ODA SDKs. If you are not an ODA member, you can use them for non-commercial applications only.
We do not distribute ODA File Converter; we distribute our SDKs which work with .dwg, .dxf, .dgn and many other file formats (not only read and save, but also edit, visualize, etc.). We provide only the latest version on our website, earlier versions are only available for ODA Members.