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Calendaring Extensions

Document Charter Calendaring Extensions WG (calext)
Title Calendaring Extensions
Last updated 2022-03-02
State Approved
WG State Active
IESG Responsible AD Francesca Palombini
Charter edit AD Francesca Palombini
Send notices to (None)

The CALEXT working group is chartered to maintain and extend the specifications
for formats and protocols related to calendaring and contacts within the IETF,
starting from the basis of:

- CalDAV (RFC 4791)
- iCalendar (RFC 5545)
- iTIP (RFC 5546)
- iMIP (RFC 6047)
- VCARD (RFC 6350)
- CardDAV (RFC 6352)
- JSCalendar (RFC 8984)
- JSContact (draft-ietf-jmap-jscontact)

and the many existing extensions and companion documents to these.

This working group is envisaged to be long-running, and deal with a steady flow
of changes.  Experience has shown that these specifications are still seeing
significant need for updates, as new use-cases are identified and user
requirements change.

This working group will do the following:

- maintain existing standards and proposed standards, processing errata and
refreshing them as required

- evaluate and develop extensions to the existing standards to provide for new
use-cases where there is demand

- generate documents describing existing vendor extensions which are in common
usage, and likely to be encountered in the wild.

The working group will work under the following parameters:

- The extensions developed are expected to be backwards-compatible with the
existing standards. Incompatibilities must be identified, minimized, and

- Any extensions to icalendar or jscalendar must include a representation in
both formats, and define a robust mapping between them.

- Any extensions to vcard or jscontact must include a representation in both
formats, and define a robust mapping between them.

- All calendar extensions must examine their impact on the iTIP protocol (RFC
5546), and define any necessary extensions to iTIP to accommodate such impact.

The working group will maintain relationships with other working groups:

- HTTPBIS and HTTPAPI: when extending the CalDAV or CardDAV protocols to ensure
that changes are consistent with good http practices.

- JMAP: when making updates to JSCalendar and JSContact to ensure that the
changes are compatible with the JMAP methods for managing data in these formats.

- EXTRA, DMARC and EMAILCORE: for changes related to iTIP delivery via email.

- TZDIST and SEDATE for date, time, and timezone related issues.

- Other IETF working groups as appropriate, when their work interacts with ours.

- Other standards organisations like CalConnect and M3AAWG that are doing work
in the same fields.

The following are out of scope for the working group:

- Any attempt to develop non-Gregorian calendar systems/calculations.

- Work which is in scope for any other ART area working group, and better
suited to that group.

- Work which is unrelated to anything that this group is currently maintaining.