I think I've found the answer on your ordering page:
"Service Contract option
If you order an Annual Service Contract for a Direct Oracle Access license, you are entitled to technical support by e-mail and free product upgrades for the period of 1 year. Without this contract, you will receive only patch releases of the Direct Oracle Access version you purchased.
You can order the service contract directly with Direct Oracle Access or at a later time. The service contract can be renewed when it expires after 1 year. "
So it appears I can upgrade for free.
thx