About Upgrading Your RDBMS in the Siebel Environment
If your currently installed RDBMS version isn't supported in the new release, then you must upgrade your RDBMS before performing the Siebel database upgrade. You can find platform, database, and other certifications for Siebel on My Oracle Support. For help searching for certifications, see How to Check the Certification Matrix in the New My Oracle Support Site (KB871388).
Environments: Development, Test and Production.
If your currently installed RDBMS version is supported in the new release, and you plan to upgrade your RDBMS, then you can do so before or after upgrading your Siebel database.
The following guidelines and requirements are for planning your RDBMS upgrade.
Note: When you upgrade the RDBMS, also be sure to upgrade your client database connectivity
software.