For Oracle 12c support the odbc driver needs to be updated manually and I would recommend you to have the appropriate ojdbc jars installed on your IS in order to prevent unexpected behaviour of Adapter services.
Also have a look at “webMethods Adapters System Requirements” and “Software AG System Requirements”. Also taking a prior consultation from SAG support will give you more details as they might be aware of issues on not updating the jars w.r.t to Oracle 12c. For your information we are on Oracle 12c with latest jars installed.
#webMethods#Integration-Server-and-ESB#webMethods-Upgrade#webMethods-General