Serialising Extended Data About Times and Events
charter-ietf-sedate-00-02

RFC3339 defines a format that can reliably express an instant in time, either in UTC or in a local time along with the offset against UTC. However, datetime data often has additional context, such as the timezone or calendar system that was in use when that instant was recorded. Particularly when using times for interval, recurrence, or offset calculations, it is necessary to know the context in which the timepoint exists.

It is valuable to have a serialisation format that retains this context and can reliably round-trip the additional context to systems that understand it, via intermediate systems that only need to know about the instant in time.

The TC39 working group at ECMA have developed a format that is a good basis for this work: draft-ryzokuken-datetime-extended.

It is anticipated that this document would be a companion to RFC3339 rather than a replacement, embedding an unaltered RFC3339 instant along with the contextual data.

It is also within scope for this working group to consider a minor update to RFC3339 to allow larger than four-digit signed years, to enable representing times further into the past and future.

It is anticipated that this working group will publish one or two documents on the work mentioned above. After that, the working group will close down or recharter.

The working group will coordinate with ECMA International TC39 and ISO TC154.