Low level versioning

There has been some recent discussion in my organisation as to whether
there is a need to provide verion information for each
element/aggregate in our standard data model.

Currently versioning is only visible to implementers on the business
transaction level schema (namespace), that is, individual parts are
not individually versioned.

Does UBL provide individual version information for each business
entity, and are each of these visible when entities are combined to
form a business transaction ?

I have a feeling that traceability to the core data model needs to
reflect version, but I remain to be convinced about whether it is
necessary at this level at run-time.

All opinions welcome.

Fraser.