The Date line (formerly "Posted") is the date, in a format that must be acceptable both to the ARPANET and to the getdate routine, that the article was originally posted to the network. This date remains unchanged as the article is propagated throughout the network. One format that is acceptable to both is
Weekday, DD-Mon-YY HH:MM:SS TIMEZONE
Several examples of valid dates appear in the sample article above. Note in particular that ctime format:
Wdy Mon DD HH:MM:SS YYYY
is not acceptable because it is not a valid ARPANET date. However, since older software still generates this format, news implementations are encouraged to accept this format and translate it into an acceptable format.
The contents of the TIMEZONE field is currently subject to worldwide time zone abbreviations, including the usual American zones (PST, PDT, MST, MDT, CST, CDT, EST, EDT), the other North American zones (Bering through Newfoundland), European zones, Australian zones, and so on. Lacking a complete list at present (and unsure if an unambiguous list exists), authors of software are encouraged to keep this code flexible, and in particular not to assume that time zone names are exactly three letters long. Implementations are free to edit this field, keeping the time the same, but changing the time zone (with an appropriate adjustment to the local time shown) to a known time zone.