All I do know are the differences with the German version. Geometries is still geometries, but textures is texturen ! All the library folders have different names as well. As far as I know, there are no differences in Poser file internals. Those are taken care of by Poser itself. This is only for Poser 4 and ProPack... Poser 5 does use the same folder names for all versions.

Yesterday's the past, tomorrow's the future, but today is a gift. That's why it's called the present.