What Is Interoperability for Oracle Database Upgrades?

In the context of upgrading Oracle Database to Oracle AI Database, interoperability is the ability of different database releases to communicate and work in a distributed environment.

A distributed database system can comprise different releases of Oracle Database and Oracle AI Database, and all supported database releases can participate in the distributed database system. However, the applications that work with a distributed database must also be able to interoperate with the features and functions that are available at each node in the system.

Interoperability across disparate operating systems and operating system versions can cause problems (especially during rolling upgrades) because the minimum requirements for the new database can require you to upgrade the operating systems on some or all of your hosts. For this reason, before you start a database upgrade, you must check to ensure that drivers, network, and storage are compatible for all the interim upgrade states of the system during the rolling upgrade.

Note:

Because Oracle AI Database Upgrade Guide discusses upgrading and downgrading between different database releases, the definition of interoperability is for Oracle Database and Oracle AI Database releases. Other Oracle documentation may use a broader definition of the term interoperability. For example, interoperability in some cases can describe communication between different hardware platforms and operating systems.

My Oracle Support note 207303.1 "Client / Server / Interoperability Support Between Different Oracle Versions" provides additional information.