- When a MEAD message is to be sent together with an ERN message there is no compulsion to also send the files containing the cover art and any other secondary Resources;
- When the cover art or any other secondary Resource needs updating, there is no compulsion to also update any MEAD message(s); and
- When updating one MEAD message that was sent with an ERN message, there is no compulsion to also update any other MEAD messages that might have been sent with a previous version of the ERN message; and
- When updating an ERN message (e.g. to provide a new Deal), there is no need to also update all associated MEAD messages. The MEAD information previously sent with an ERN message about the same Release(s) remains, thus, valid unless the sender of the ERN message choses to accompany its ERN message with an updated MEAD message. In that case the rules indicated in the article on ‘MEAD as a “Statement of Truth”’ apply.
Note: this rule will be added at some stage to the ERN Choreography standard.