Recommendations for Oracle Net Services When Upgrading Oracle Database

You must ensure that the listener is running in your new release Oracle home.

If the Oracle Database that you are upgrading does not have a listener configured, then before you start the upgrade, you must run Oracle Net Configuration Assistant (NETCA) to configure the listening protocol address and service information for the new release of Oracle Database, including a listener.ora file. The current listener is backward-compatible with earlier Oracle Database releases.

If you are upgrading Oracle Real Application Clusters Oracle Database, or a release older than Oracle Database 12c, then review the following additional information.

For Oracle RAC database upgrades, the listener normally is migrated during the Grid Infrastructure upgrade. You must administer the listener by using the lsnrctl command in the Oracle Grid Infrastructure home. Do not attempt to use the lsnrctl commands from Oracle home locations for earlier releases.