ERN-3 as well as ERN-4 contains a number of fields that can communicate dates or date-times. Some of these are to communicate “historic” information: when was “Hey Jude” recorded? When was it released? These fields are typically dates and support a variety of flags to indicate precision (e.g. IsBeforeand IsApproximate).
Other dates/date-times have a direct legal consequence in the context of an ERN message: the start and end dates of the validity period of a commercial deal, for instance.
These periods can currently be provided in several forms:
DDEX has agreed to phase-out the “dates only” means of communicating such information over time. DDEX therefore recommends that implementers only use date-times.
(1) Note, it is technically also possible to have a period tag with no start and no end. This approach is, however, not acceptable; from ERN 4.2 onwards this will be impossible.