Hi,
what ORM framework are you using? As far as I know Skipper offers all data types offered by ORMs. But if missed something, we will add it asap.
Regarding your compatibility question. You can always open the project in newer Skipper version without any complications. Skipper has internal update routines which update the model to the latest version.
Generated XML is usually the same when there were no changes in ORM framework itself.