As part of role-based security, the way in which privileged system procedures run has changed.
In pre-16.0 databases, privileged system procedures ran with the privileges of its owner, referred to as the SYSTEM PROCEDURE DEFINER model. In new 16.0 databases, privileged system procedures run with the privileges of the person executing it, referred to as the SYSTEM PROCEDURE INVOKER model.
To minimize potential loss of functionality as a result of this behavior change, after upgrading using the default options, all pre-16.0 system procedures continue to run using the SYSTEM PROCEDURE DEFINER model. Any system procedures introduced in 16.0 or later run using the SYSTEM PROCEDURE INVOKER model.