Calendaring Extensions (calext)
-------------------------------

 Charter

 Current Status: Active

 Chairs:
     Bron Gondwana <brong@fastmailteam.com>
     Daniel Migault <daniel.migault@ericsson.com>

 Applications and Real-Time Area Directors:
     Barry Leiba <barryleiba@computer.org>
     Alexey Melnikov <aamelnikov@fastmail.fm>
     Adam Roach <adam@nostrum.com>

 Applications and Real-Time Area Advisor:
     Barry Leiba <barryleiba@computer.org>

 Mailing Lists:
     General Discussion: calsify@ietf.org
     To Subscribe:       http://www.ietf.org/mailman/listinfo/calsify
     Archive:            https://mailarchive.ietf.org/arch/browse/calsify/

Description of Working Group:

  The Calendaring Extensions working group is chartered to develop
  extensions to the iCalendar (RFC 5545), iTIP (RFC 5546), and
  CalDAV (RFC 4791) standards.

  This working group will do the following:

  - Develop an extension to iCalendar to support non-Gregorian recurrence
  rules, without the need to support new calendar scale values in
  iCalendar as a whole. This will allow for easy implementation of the
  primary use case for non-Gregorian support in calendar systems, without
  the need for significant changes to the iCalendar format. The
  non-Gregorian calendar system should be based on the International
  Components for Unicode work by the Unicode Consortium
  (http://site.icu-project.org).

  - Develop an extension to iCalendar to support a new component type that
  allows users to express arbitrary, possibly repeating, periods of
  "available" time. The primary use case for this is for users to express
  their "office hours" (e.g., Monday-Friday, 9am-5pm) in a standard way to
  ensure free busy lookups show the correct periods of availability.

  - Define a set of new iCalendar properties and parameters to standardise
  some existing experimental X- properties in common use, based on a
  survey of existing implementations.

  - Define a set of new iCalendar properties and parameters to cover key
  uses cases that implementers have identified, including, but not
  limited to, a new "IMAGE" property (to allow embedding/linking of
  images tied to a specific event), and a "CONFERENCE" property (to allow
  embedding information about dial-in numbers and similar multi-party
  communication options for an event).

  The working group will work under the following parameters:

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

  - For each set of extensions, examine their impact on the iTIP protocol
  (RFC 5546), and define any necessary extensions to iTIP to accommodate
  such impact.

  - For each set of extensions, examine their impact on the CalDAV
  protocol (RFC 4791), and define any necessary extensions to CalDAV to
  accommodate such impact.  Interface with the httpbis working group to
  ensure that any CalDAV changes are consistent with good http practices.

  The working group will use the following drafts as initial input for its
  work:
  draft-daboo-icalendar-rscale-03
  draft-daboo-calendar-availability-05
  draft-daboo-icalendar-extensions-08

  The following are out of scope for the working group:

  - Any change that impacts backwards compatibility with existing
  deployed iCalendar/iTIP/CalDAV clients and servers will be discussed
  by the working group with a view to minimizing disruption to deployed
  implementations without compromising desirable new function.

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

Goals and Milestones:
  Dec 2019 - Send JSCalendar draft to IESG
  Dec 2019 - Submit valarm document to IESG for publication
  Feb 2020 - Submit scheduling controls document to IESG for publication
  Apr 2020 - Update charter/milestones to reflect current and planned work
  Apr 2020 - Submit vpoll document to IESG for publication
  Jun 2020 - Submit calendar series document to IESG for publication
  Done     - Submit non-Gregorian recurrence rule draft to IESG for publication
  Done     - WG adoption of an availability draft
  Done     - WG adoption of an extensions draft
  Done     - Submit availability draft to IESG for publication
  Done     - Submit extensions draft to IESG for publication
  Done     - Send attachment dratf to IESG
  Done     - Adopt a document for subscription upgrade
  Done     - Send Event Publication draft to IESG
  Done     - Send iCal relation draft to IESG
  Done     - Adopt a document for consensus scheduling