The second alpha version of this module changes the default file upload form to support only one file attachment per node. It makes more sense and makes the form validation much easier. This revision has a bunch of bugfixes and associated code cleanup and refactoring.
Unfortunately, at the moment once uploaded, the file stays untouched. I'm considering to maybe do an add-on module, which will provide the file revisions UI. This is done to keep the module as simple as possible, and the default upload form is designed for a different workflow.
This is an alpha release. That means that there might be more features added. There are unknown number of bugs. Having said that it is not that unusable. It has the major features I've planned for the life of the D5 module, some changes will come through, but no big ones. Very little will change and soon there should be a beta.