DBA_REGISTRY_HISTORY provides information about upgrades, downgrades, and critical patch updates that have been performed on the database.

Column Datatype NULL Description
ACTION_TIME TIMESTAMP(6)   The time the upgrade, downgrade, or patch action was completed
ACTION VARCHAR2(30)   The specific action (for example, UPGRADE or DOWNGRADE)
NAMESPACE VARCHAR2(30)   The namespace of the components affected (for example, SERVER)
VERSION VARCHAR2(30)   The version number of the server (for example,
ID NUMBER   The identification number of the Critical Patch Update
COMMENTS VARCHAR2(255)   Additional comments about the action taken