Non-Gregorian Recurrence Rules in iCalendar
draft-ietf-calext-rscale-03

The information below is for an old version of the document
Document Type Active Internet-Draft (calext WG)
Last updated 2015-02-06 (latest revision 2015-01-07)
Replaces draft-daboo-icalendar-rscale
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication
Document shepherd Donald Eastlake
Shepherd write-up Show (last changed 2015-01-27)
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Responsible AD Barry Leiba
Send notices to "Donald E. Eastlake 3rd" <d3e3e3@gmail.com>
Network Working Group                                           C. Daboo
Internet-Draft                                                Apple Inc.
Updates: 5545, 6321, 7265 (if approved)                      G. Yakushev
Intended status: Standards Track                             Google Inc.
Expires: July 11, 2015                                   January 7, 2015

              Non-Gregorian Recurrence Rules in iCalendar
                      draft-ietf-calext-rscale-03

Abstract

   This document defines extensions to iCalendar (RFC 5545) to support
   use of non-Gregorian recurrence rules.  It also defines how CalDAV
   (RFC 4791) servers and clients can be extended to support these new
   recurrence rules.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on July 11, 2015.

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Daboo & Yakushev          Expires July 11, 2015                 [Page 1]
Internet-Draft        iCalendar Property Extensions         January 2015

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Extended RRULE Property . . . . . . . . . . . . . . . . . . .   6
     4.1.  Handling Leap Months  . . . . . . . . . . . . . . . . . .   7
     4.2.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .   7
   5.  Registering Calendar Systems  . . . . . . . . . . . . . . . .  10
   6.  Use with iTIP . . . . . . . . . . . . . . . . . . . . . . . .  10
   7.  Use with xCal . . . . . . . . . . . . . . . . . . . . . . . .  11
   8.  Use with jCal . . . . . . . . . . . . . . . . . . . . . . . .  12
   9.  Use with CalDAV . . . . . . . . . . . . . . . . . . . . . . .  13
     9.1.  CALDAV:supported-rscale-set Property  . . . . . . . . . .  13
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  14
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  14
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     13.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     13.2.  Informative References . . . . . . . . . . . . . . . . .  15
   Appendix A.  Change History (To be removed by RFC Editor before
                publication) . . . . . . . . . . . . . . . . . . . .  15
   Appendix B.  xCal RELAX NG schema update  . . . . . . . . . . . .  17
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

1.  Introduction

   The iCalendar [RFC5545] data format is in widespread use to represent
   calendar data. iCalendar represents dates and times using the
   Gregorian calendar system only.  It does provide a way to use non-
   Gregorian calendar systems via a "CALSCALE" property, but this has
   never been used.  However, there is a need to support at least non-
   Gregorian recurrence patterns to cover anniversaries, and many local,
   religious, or civil holidays based on non-Gregorian dates.

   There are several disadvantages to using the existing "CALSCALE"
   property in iCalendar for implementing non-Gregorian calendars:

   1.  The "CALSCALE" property exists in the top-level "VCALENDAR"
       objects and thus applies to all components within that object.
       In today's multi-cultural society, that restricts the ability to
       mix events from different calendar systems within the same
       iCalendar object. e.g., it would prevent having both the
       Gregorian New Year and Chinese New Year in the same iCalendar
       object.

   2.  Time zone and daylight saving time rules are typically published
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