In order to provision the VDB, you would need to upgrade it to 12cR2. Note that you do not necessarily need to upgrade the dSource itself, just the VDB. You can find information on how to upgrade your VDB on our help article "Upgrading an Oracle VDB" .
I hope that helps. Let me know if you have any questions.
To clarify, the product won't allow you to provision to a target environment that doesn't have a compatible Oracle installation. In order to accomplish this, you would have to have a parallel Oracle 11g installation on the target environment, to which you could provision the VDB, then upgrade the VDB to 12c using the instruction in the hyperlink provided.