To configure a new class for auditing
Any future instances of the class will contain the audit definitions that you specified in the class.
To configure or modify an existing class for auditing
The audit history of new and existing instances of the class will be updated with the configured audit event logs as they occur. The audit history of existing instances will not be updated retroactively with data about audit events that occurred prior to the class being configured for auditing
See Create a Class and Audit Definitions for more information.