7.3 Contractually mandatory

The messages defined in this standard contain fields with cardinality “0-1” or “0-n”. Therefore, these fields are from the point of view of the implementation of the standards, optional. Such fields may, however, be mandatory when a DDEX message is sent in a specific commercial context.

In such circumstances, a message is deemed conformant only if and when it contains all the contractually mandatory fields as agreed between the message sender and the message recipient.