Ok, so what do you mean by "JPA 2.1 support"? That we're pulling in that API version via ORM 4.3 or that we're actively supporting any of the new features of JPA 2.1 (which I don't think we do)? Which version would you suggest for OGM once we're based on ORM 5?

Given that we're tied closely to ORM APIs and thus likely only can work with one ORM version at a time, why not make that explicit by using the same version?