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Versions: 00

Network Working Group                                            E. York
Internet-Draft                                    California Things, Inc
Intended status: Standards Track                                C. Daboo
Expires: November 24, 2019                                    Apple Inc.
                                                             M. Douglass
                                                     Spherical Cow Group
                                                            May 23, 2019


          VPOLL: Consensus Scheduling Component for iCalendar
                         draft-calext-vpoll-00

Abstract

   This specification introduces a new iCalendar component which allows
   for consensus scheduling, that is, voting on a number of alternative
   meeting or task alternatives.

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 November 24, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terms and definitions . . . . . . . . . . . . . . . . . . . .   4
     2.1.  consensus scheduling  . . . . . . . . . . . . . . . . . .   4
     2.2.  active Vpoll  . . . . . . . . . . . . . . . . . . . . . .   5
     2.3.  voter . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Simple Consensus Scheduling . . . . . . . . . . . . . . . . .   5
     3.1.  The VPOLL Component: An Overview  . . . . . . . . . . . .   5
     3.2.  The VPOLL Subcomponents: An Overview  . . . . . . . . . .   7
     3.3.  VPOLL responses . . . . . . . . . . . . . . . . . . . . .   8
     3.4.  VPOLL updates . . . . . . . . . . . . . . . . . . . . . .   9
     3.5.  VPOLL Completion  . . . . . . . . . . . . . . . . . . . .  11
     3.6.  Other Responses . . . . . . . . . . . . . . . . . . . . .  11
   4.  iCalendar Extensions  . . . . . . . . . . . . . . . . . . . .  12
     4.1.  Updated Relation Type Value . . . . . . . . . . . . . . .  12
     4.2.  Updated Status Value  . . . . . . . . . . . . . . . . . .  12
     4.3.  New Property Parameters . . . . . . . . . . . . . . . . .  13
       4.3.1.  Required  . . . . . . . . . . . . . . . . . . . . . .  13
       4.3.2.  Stay-Informed . . . . . . . . . . . . . . . . . . . .  13
     4.4.  New Properties  . . . . . . . . . . . . . . . . . . . . .  14
       4.4.1.  Accept-Response . . . . . . . . . . . . . . . . . . .  14
       4.4.2.  Poll-Completion . . . . . . . . . . . . . . . . . . .  15
       4.4.3.  Poll-Item-Id  . . . . . . . . . . . . . . . . . . . .  16
       4.4.4.  Poll-Mode . . . . . . . . . . . . . . . . . . . . . .  16
       4.4.5.  Poll-properties . . . . . . . . . . . . . . . . . . .  17
       4.4.6.  Poll-Winner . . . . . . . . . . . . . . . . . . . . .  18
       4.4.7.  Reply-URL . . . . . . . . . . . . . . . . . . . . . .  18
       4.4.8.  Response  . . . . . . . . . . . . . . . . . . . . . .  19
       4.4.9.  Voter . . . . . . . . . . . . . . . . . . . . . . . .  20
     4.5.  New Components  . . . . . . . . . . . . . . . . . . . . .  21
       4.5.1.  VPOLL Component . . . . . . . . . . . . . . . . . . .  21
       4.5.2.  VVOTER Component  . . . . . . . . . . . . . . . . . .  24
       4.5.3.  VOTE Component  . . . . . . . . . . . . . . . . . . .  25
   5.  Poll Modes  . . . . . . . . . . . . . . . . . . . . . . . . .  26
     5.1.  POLL-MODE:BASIC . . . . . . . . . . . . . . . . . . . . .  26
       5.1.1.  Property restrictions . . . . . . . . . . . . . . . .  27
       5.1.2.  Outcome reporting . . . . . . . . . . . . . . . . . .  27
   6.  iTIP Extensions . . . . . . . . . . . . . . . . . . . . . . .  27
     6.1.  Methods . . . . . . . . . . . . . . . . . . . . . . . . .  27
     6.2.  Interoperability Models . . . . . . . . . . . . . . . . .  28
       6.2.1.  Delegation  . . . . . . . . . . . . . . . . . . . . .  28
       6.2.2.  Acting on Behalf of Other Calendar Users  . . . . . .  29
       6.2.3.  Component Revisions . . . . . . . . . . . . . . . . .  29
       6.2.4.  Message Sequencing  . . . . . . . . . . . . . . . . .  29



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     6.3.  Application Protocol Elements . . . . . . . . . . . . . .  29
       6.3.1.  Methods for VPOLL Calendar Components . . . . . . . .  29
       6.3.2.  Method: PUBLISH . . . . . . . . . . . . . . . . . . .  30
       6.3.3.  Method: REQUEST . . . . . . . . . . . . . . . . . . .  32
         6.3.3.1.  Rescheduling a poll . . . . . . . . . . . . . . .  35
         6.3.3.2.  Updating or Reconfirmation of a Poll  . . . . . .  35
         6.3.3.3.  Confirmation of a Poll  . . . . . . . . . . . . .  35
         6.3.3.4.  Closing a Poll  . . . . . . . . . . . . . . . . .  35
         6.3.3.5.  Delegating a Poll to Another CU . . . . . . . . .  36
         6.3.3.6.  Changing the Organizer  . . . . . . . . . . . . .  36
         6.3.3.7.  Sending on Behalf of the Organizer  . . . . . . .  37
         6.3.3.8.  Forwarding to an Uninvited CU . . . . . . . . . .  37
         6.3.3.9.  Updating Voter Status . . . . . . . . . . . . . .  37
       6.3.4.  Method: REPLY . . . . . . . . . . . . . . . . . . . .  38
       6.3.5.  Method: CANCEL  . . . . . . . . . . . . . . . . . . .  40
       6.3.6.  Method: REFRESH . . . . . . . . . . . . . . . . . . .  42
       6.3.7.  Method: POLLSTATUS  . . . . . . . . . . . . . . . . .  43
   7.  CalDAV Extensions . . . . . . . . . . . . . . . . . . . . . .  44
     7.1.  Calendar Collection Properties  . . . . . . . . . . . . .  45
       7.1.1.  CALDAV:supported-vpoll-component-sets . . . . . . . .  45
       7.1.2.  CALDAV:vpoll-max-items  . . . . . . . . . . . . . . .  46
       7.1.3.  CALDAV:vpoll-max-active . . . . . . . . . . . . . . .  47
       7.1.4.  CALDAV:vpoll-max-voters . . . . . . . . . . . . . . .  48
       7.1.5.  CalDAV:even-more-properties . . . . . . . . . . . . .  49
       7.1.6.  Extensions to CalDAV scheduling . . . . . . . . . . .  49
     7.2.  Additional Preconditions for PUT, COPY, and MOVE  . . . .  49
     7.3.  CalDAV:calendar-query Report  . . . . . . . . . . . . . .  50
       7.3.1.  Example: Partial Retrieval of VPOLL . . . . . . . . .  50
     7.4.  CalDAV time ranges  . . . . . . . . . . . . . . . . . . .  52
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  53
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  53
     9.1.  Parameter Registrations . . . . . . . . . . . . . . . . .  54
     9.2.  Property Registrations  . . . . . . . . . . . . . . . . .  54
     9.3.  POLL-MODE Registration Template . . . . . . . . . . . . .  54
     9.4.  POLL-MODE Registrations . . . . . . . . . . . . . . . . .  54
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  55
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  55
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  55
     11.2.  Informative References . . . . . . . . . . . . . . . . .  56
   Appendix A.  Open issues  . . . . . . . . . . . . . . . . . . . .  56
   Appendix B.  Change log . . . . . . . . . . . . . . . . . . . . .  58
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  59

1.  Introduction

   The currently existing approach to agreeing on meeting times using
   iTip [RFC5546] and/or iMip [RFC6047] has some significant failings.
   There is no useful bargaining or suggestion mechanism in iTip, only



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   the ability for a potential attendee to accept or refuse or to
   counter with a time of their own choosing.

   Part of the problem is that for many potential attendees, their
   freebusy is not an accurate representation of their availability.  In
   fact, when trying to schedule conference calls across different
   organizations, attendees may not be allowed to provide freebusy
   information or availability as this may reveal something of the
   organizations internal activities.

   A number of studies have shown that large amounts of time are spent
   trying to come to an agreement - up to and beyond 20 working hours
   per meeting.  Many organizers fall back on other approaches such as
   phone calls and email to determine a suitable time.

   Online services have appeared as a result and these allow
   participants to vote on a number of alternatives without revealing or
   using freebusy or availability.  When agreement is reached a
   conventional scheduling message may be sent to the attendees.  This
   approach appears to reach consensus fairly rapidly.  Peer pressure
   may have some bearing on this as all voters are usually able to see
   the current state of the voting and may adjust their own meeting
   schedules to make themselves available for a popular choice.

   The component and properties defined in this specification provide a
   standardized structure for this process and allow calendar clients
   and servers and web based services to interact.

   These structures also have uses beyond the relatively simple needs of
   most meeting organizers.  The process of coming to consensus can also
   be viewed as a bidding process.

2.  Terms and definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].

   Additionally the following terms are used:

2.1.  consensus scheduling

   The process whereby users come to some agreement on meeting or task
   alternatives and then book that meeting or task.






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2.2.  active Vpoll

   A VPoll may have a DTSTART, DTEND and DURATION which may define the
   start and end of the active voting period

2.3.  voter

   A participant who votes on the alternatives.  A voter need not be an
   attendee of any of the alternatives presented.

3.  Simple Consensus Scheduling

   This specification defines components and properties which can be
   used for simple consensus scheduling but also have the generality to
   handle more complex cases.  To provide an easy (and for many -
   sufficient) introduction to consensus scheduling and VPOLL we will
   outline the flow of information for the simple case of voting on a
   number of meeting alternatives which differ only in time.  In
   addition the voters will all be potential attendees.

   This specification not only defines data structures but adds a new
   iTip method used when consensus has been reached.  This document will
   show how a VPOLL object is used to inform voters of the state of a
   simple vote on some alternatives.

3.1.  The VPOLL Component: An Overview

   The VPOLL component acts as a wrapper for a number of alternatives to
   be voted on, together with some properties and a new component used
   to maintain the state of the voting.  For our simple example the
   following VPOLL properties and sub-components are either required or
   appropriate:

   DTSTAMP
      The usual [RFC5545] property.

   SEQUENCE
      The usual [RFC5545] property.  See below for SEQUENCE behavior.

   UID
      The usual [RFC5545] property.

   ORGANIZER
      The usual [RFC5545] property.  In general this need not be an
      organizer of any of the alternatives.  In this simple outline we
      assume it is the same.

   SUMMARY



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      The usual [RFC5545] property.  This optional but recommended
      property provides the a short title to the poll.

   DESCRIPTION
      The usual [RFC5545] property.  This optional property provides
      more details.

   DTEND
      The usual [RFC5545] property.  This optional property provides a
      poll closing time and date after which the VPOLL is no longer
      active.

   POLL-MODE
      A new property which defines how the votes are used to obtain a
      result.  For our use case it will take the value "BASIC" meaning
      one event will be chosen from the alternatives.

   POLL-COMPLETION
      A new property which defines who (server or client) chooses and/or
      submits the winning choice.  In our example the value is "SERVER-
      SUBMIT" which means the client chooses the winner but the server
      will submit the winning choice.

   POLL-PROPERTIES
      A new property which defines which icalendar properties are being
      voted on.  For our use case it will take the value "DTSTART,
      LOCATION" meaning only those properties are significant for
      voting.  Other properties in the events may differ but are not
      considered significant for the voting process.

   VVOTER
      A new component.  There is one of these for each voter and it
      contains a VOTER property to identify the voter and one VOTE
      component for each item being voted on.

   VOTE
      A new component.  There is one of these for each voter and choice.
      It usually contains at least a POLL-ITEM-ID property to identify
      the choice and a RESPONSE property to provide a vote.  For more
      complex poll modes it may contain other information such as cost
      or estimated duration.

   VOTER
      A new property.  There is one of these for each voter and it is
      similar to the [RFC5545] ATTENDEE property.  It identifies the
      VVOTER component to show who is taking part in the voting and
      their results.




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   VEVENT
      In our simple use case there will be multiple VEVENT sub-
      components defining the alternatives.  Each will have a different
      date and or time for the meeting.

   VPOLL with 3 voters and 3 alternative meetings:

   BEGIN:VCALENDAR
   VERSION:2.0
   PRODID:-//Example//Example
   METHOD:REQUEST
   BEGIN:VPOLL
   POLL-MODE:BASIC
   POLL-COMPLETION:SERVER-SUBMIT
   POLL-PROPERTIES:DTSTART,LOCATION
   ORGANIZER:mailto:mike@example.com
   UID:sched01-1234567890
   DTSTAMP:20120101T000000Z
   SUMMARY:What to do this week
   DTEND:20120101T000000Z
   BEGIN: VVOTER
   VOTER:mailto:cyrus@example.com
   END VVOTER
   BEGIN: VVOTER
   VOTER:mailto:eric@example.com
   END VVOTER
   BEGIN: VVOTER
   VOTER:mailto:mike@example.com
   END VVOTER
   BEGIN:VEVENT.......(with a poll-item-id=1)
   END:VEVENT
   BEGIN:VEVENT.......(with a poll-item-id=2)
   END:VEVENT
   BEGIN:VEVENT.......(with a poll-item-id=3)
   END:VEVENT
   END:VPOLL
   END:VCALENDAR

   As can be seen in the example above, there is an iTip METHOD property
   with the value REQUEST.  The VPOLL object will be distributed to all
   the voters, either through iMip or through some VPOLL enabled
   service.

3.2.  The VPOLL Subcomponents: An Overview

   Within the VPOLL component we have the alternatives to vote on.  In
   many respects these are standard [RFC5545] components.  For our
   simple use case they are all VEVENT components.  In addition to the



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   usual [RFC5545] properties some extra properties are used for a
   VPOLL.

   POLL-ITEM-ID
      This provides a unique reference to the sub-component within the
      VPOLL.  It's value SHOULD be a small integer.

3.3.  VPOLL responses

   Upon receipt of a VPOLL REQUEST the voter will reply with a VPOLL
   component containing their vote.  In our simple case it will have the
   following properties and components:

   DTSTAMP
      The usual [RFC5545] property.

   SEQUENCE
      The usual [RFC5545] property.  See below for SEQUENCE behavior.

   UID
      Same as the request.

   ORGANIZER
      Same as the request.

   SUMMARY
      Same as the request.

   VVOTER
      One only.

   VOTER
      One only inside the VVOTER component - the voter replying.

   VOTE
      One per item being voted on.  There does not need to be one for
      each choice.

   POLL-ITEM-ID
      One inside each VOTE component to identify the choice.

   RESPONSE
      One inside each VOTE component to specify the vote.

   Note that a voter can send a number of REPLYs for each REQUEST sent
   by the organizer.  Each REPLY completely replaces the voting record
   for that voter for all components being voted on.  In our example, if




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   Eric responds and votes for items 1 and 2 and then responds again
   with a vote for only item 3, the final outcome is one vote on item 3.

   REPLY VPOLL from Cyrus:

   BEGIN:VCALENDAR
   VERSION:2.0
   PRODID:-//Example//Example
   METHOD: REPLY
   BEGIN:VPOLL
   ORGANIZER:mailto:mike@example.com
   UID:sched01-1234567890
   DTSTAMP:20120101T010000Z
   SUMMARY:What to do this week
   BEGIN:VVOTER
   VOTER:mailto:cyrus@example.com
   BEGIN:VOTE
   POLL-ITEM-ID:1
   RESPONSE:50
   COMMENT:Work on iTIP
   END:VOTE
   BEGIN:VOTE
   POLL-ITEM-ID:2
   RESPONSE:100
   COMMENT:Work on WebDAV
   END:VOTE
   BEGIN:VOTE
   POLL-ITEM-ID:3
   RESPONSE:0
   END:VOTE
   END:VVOTER
   END:VPOLL
   END:VCALENDAR

3.4.  VPOLL updates

   When the organizer receives a response from one or more voters the
   current state of the poll is sent to all voters.  The new iTip method
   POLLSTATUS is used.  The VPOLL can contain a reduced set of
   properties but MUST contain DTSTAMP, SEQUENCE (if not 0), UID,
   ORGANIZER and one or more VVOTER components each populated with a
   VOTER property and zero or more VOTE components.









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   BEGIN:VCALENDAR
   VERSION:2.0
   PRODID:-//Example//Example
   METHOD: POLLSTATUS
   BEGIN:VPOLL
   ORGANIZER:mailto:mike@example.com
   UID:sched01-1234567890
   DTSTAMP:20120101T020000Z
   SEQUENCE:0
   SUMMARY:What to do this week
   BEGIN:VVOTER
   VOTER:mailto:cyrus@example.com
   BEGIN: VOTE
   POLL-ITEM-ID:1
   RESPONSE:50
   COMMENT:Work on iTIP
   END:VOTE
   BEGIN:VOTE
   POLL-ITEM-ID:2
   RESPONSE:100
   COMMENT:Work on WebDAV
   END:VOTE
   BEGIN:VOTE
   POLL-ITEM-ID:3
   RESPONSE:0
   END:VOTE
   END:VVOTER
   BEGIN:VVOTER
   VOTER:mailto:eric@example.com
   BEGIN:VOTE
   POLL-ITEM-ID:1
   RESPONSE:100
   END:VOTE
   BEGIN:VOTE
   POLL-ITEM-ID:2
   RESPONSE:100
   END:VOTE
   BEGIN:VOTE
   POLL-ITEM-ID:3
   RESPONSE:0
   END:VOTE
   END:VVOTER
   END:VPOLL
   END:VCALENDAR







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3.5.  VPOLL Completion

   After a number of REPLY messages have been received the poll will be
   considered complete.  If there is a DTEND on the poll the system may
   automatically close the poll, or the organizer may, at any time,
   consider the poll complete.  A VPOLL can be completed (and
   effectively closed for voting) by sending an iTip REQUEST message
   with the VPOLL STATUS property set to COMPLETED.

   The poll winner is confirmed by sending a final iTip REQUEST message
   with the VPOLL STATUS property set to CONFIRMED.  In this case the
   VPOLL component contains all the events being voted on along with a
   POLL-WINNER property to identify the winning event.  As the POLL-
   COMPLETION property is set to SERVER-SUBMIT the server will submit
   the winning choice and when it has done so set the STATUS to
   "SUBMITTED".

   VPOLL confirmation:

   BEGIN:VCALENDAR
   VERSION:2.0
   PRODID:-//Example//Example
   METHOD: REQUEST
   BEGIN:VPOLL
   ORGANIZER:mailto:douglm@example.com
   UID:sched01-1234567890
   DTSTAMP:20120101T030000Z
   COMPLETED:20120101T030000Z
   POLL-COMPLETION:SERVER-SUBMIT
   SEQUENCE:0
   SUMMARY:What to do this week
   STATUS:CONFIRMED
   POLL-WINNER:3
   BEGIN:VEVENT.......(with a poll-item-id=1)
   END:VEVENT
   BEGIN:VEVENT.......(with a poll-item-id=2)
   END:VEVENT
   BEGIN:VEVENT.......(with a poll-item-id=3)
   END:VEVENT
   END:VPOLL
   END:VCALENDAR

3.6.  Other Responses

   A voter being asked to choose between a number of ORGANIZER supplied
   alternatives may find none of them acceptable or may simply not care.





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   An alternative response, which may be disallowed by the ORGANIZER, is
   to send back the respondees availability or freebusy or even one or
   more new, alternative choices.

   This is accomplished by responding with a VOTE component which has no
   POLL-ITEM-ID property.  In this case it MUST contain some alternative
   information.  What form this takes depends on the poll mode in
   effect.

4.  iCalendar Extensions

4.1.  Updated Relation Type Value

   Relationship parameter type values are defined in section 3.2.15. of
   [RFC5545].  This specification updates that type to include the new
   relationship value POLL to provide a link to the VPOLL component in
   which the current component appears.

   Format Definition
      This property parameter is redefined by the following notation:

   reltypeparam       /= "RELTYPE" "=" "POLL"
   ; Property value is a VPOLL uid

   Description
      This parameter can be specified on a property that references
      another related calendar component.  The new parameter value
      indicates that the associated property references a VPOLL
      component which contains the current component.

4.2.  Updated Status Value

   Status property values are defined in section 3.8.1.11. of [RFC5545].
   This specification updates that type to define valid VPOLL status
   values.

   Format Definition
      This property parameter is redefined by the following notation:













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   statvalue /= statvalue-poll
      ; Status values for "VPOLL".
   statvalue-poll = "IN-PROCESS"
             / "COMPLETED"  ; Poll has closed,
                            ; nothing has been chosen yet
             / "CONFIRMED"  ; Poll has closed and
                            ; winning items confirmed
             / "SUBMITTED"  ; The winning item has been
                            ; submitted
             / "CANCELLED"

   Description
      These values allow clients and servers to handle the choosing and
      submission of winning choices.

   If the client is choosing and the server submitting then the
   client should set the POLL-WINNER property, set the status to
   CONFIRMED and save the poll.  When the server submits the winning
   choice it will set the status to SUBMITTED.

4.3.  New Property Parameters

4.3.1.  Required

   Parameter name
      REQUIRED

   Purpose
      To specify whether the associated property is required in the
      current context.

   Format Definition
      This parameter is defined by the following notation:

   requirededparam = "REQUIRED"  "=" ("TRUE" / "FALSE")
     ; Default is FALSE

   Description
      This parameter MAY be specified on REPLY-URL and, if the value is
      TRUE, indicates the organizer requires all replies to be made via
      the specified service rather than iTip replies.

4.3.2.  Stay-Informed

   Parameter name
      STAY-INFORMED

   Purpose



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      To specify the voter also wants to be added as an ATTENDEE when
      the poll is confirmed.

   Format Definition
      This parameter is defined by the following notation:

   stayinformedparam = "STAY-INFORMED"  "=" ("TRUE" / "FALSE")
                     ; Default is FALSE

   Description
      This parameter MAY be specified on VOTER and, if the value is
      TRUE, indicates the voter wishes to be added to the final choice
      as a non participant.

4.4.  New Properties

4.4.1.  Accept-Response

   Property name
      ACCEPT-RESPONSE

   Purpose
      This property is used in VPOLL to indicate the types of component
      that may be supplied in a response.

   Property Parameters
      Non-standard or iana parameters can be specified on this property.

   Conformance
      This property MAY be specified in a VPOLL component.

   Description
      When used in a VPOLL this property indicates what allowable
      component types may be returned in a reply.  Typically this would
      allow a voter to respond with their freebusy or availability
      rather than choosing one of the presented alternatives.

      If this property is not present voters are only allowed to respond
      to the choices in the request.

   Format Definition
      This property is defined by the following notation:

   acceptresponse = "ACCEPT-RESPONSE" acceptresponseparams ":"
                       iana-token ("," iana-token) CRLF

   acceptresponseparams = *(";" other-param)




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4.4.2.  Poll-Completion

   Property name
      POLL-COMPLETION

   Purpose
      This property is used in VPOLL to indicate whether the client or
      server is responsible for choosing and/or submitting the
      winner(s).

   Description
      When a VPOLL is stored on a server which is capable of handling
      choosing and submission of winning choices a value of SERVER
      indicates that the server should close the poll, choose the winner
      and submit whenever it is appropriate to do so.

      For example, in BASIC poll-mode, reaching the DTEND of the poll
      could trigger this server side action.
      Server initiated submission requires that the submitted choice
      MUST be a valid calendaring component.
      POLL-COMPLETION=SERVER-SUBMIT allows the client to set the poll-
      winner, set the status to CONFIRMED and then store the poll on the
      server.  The server will then submit the winning choice and set
      the status to SUBMITTED.

   Format Definition
      This property is defined by the following notation:

   poll-completion = "POLL-COMPLETION" pcparam ":" pcvalue CRLF

   pcparam = *(";" other-param)

   pcvalue = "SERVER"  ; The server is responsible for both choosing and
                      ; submitting the winner(s)
           / "SERVER-SUBMIT" ; The server is responsible for
                      ; submitting the winner(s). The client chooses.
           / "SERVER-CHOICE"  ; The server is responsible for
                      ; choosing the winner(s). The client will submit.
           / "CLIENT" ; The client is responsible for both choosing and
                      ; submitting the winner(s)
           / iana-token
           / x-name
           ;Default is CLIENT

   Example
      The following is an example of this property:

   POLL-COMPLETION: SERVER-SUBMIT



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4.4.3.  Poll-Item-Id

   Property name
      POLL-ITEM-ID

   Purpose
      This property is used in VPOLL child components as an identifier.

   Value type
      INTEGER

   Property Parameters
      Non-standard parameters can be specified on this property.

   Conformance
      This property MUST be specified in a VOTE component and in VPOLL
      choice items.

   Description
      In a METHOD:REQUEST each choice component MUST have a POLL-ITEM-ID
      property.  Each set of components with the same POLL- ITEM-ID
      value represents one overall set of items to be voted on.

      POLL-ITEM-ID SHOULD be a unique small integer for each component
      or set of components.  If it remains the same between REQUESTs
      then the previous response for that component MAY be re-used.  To
      force a re-vote on a component due to a significant change, the
      POLL-ITEM-ID MUST change.

   Format Definition
      This property is defined by the following notation:

   pollitemid = "POLL-ITEM-ID" pollitemdparams ":"
                     integer CRLF

   pollitemidparams = *(
                      (";" other-param)
               )

4.4.4.  Poll-Mode

   Property name
      POLL-MODE

   Purpose
      This property is used in VPOLL to indicate what voting mode is to
      be applied.




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   Property Parameters
      Non-standard or iana parameters can be specified on this property.

   Conformance
      This property MAY be specified in a VPOLL component or its sub-
      components.

   Description
      The poll mode defines how the votes are applied to obtain a
      result.  BASIC mode, the default, means that the voters are
      selecting one component (or group of components) with a given
      POLL=ITEM-ID.

      Other polling modes may be defined in updates to this
      specification.  These may allow for such modes as ranking or task
      assignment.

   Format Definition
      This property is defined by the following notation:

   pollmode = "POLL-MODE" pollmodeparams ":"
                ("BASIC" / iana-token / other-token) CRLF

   pollmodeparams = *(";" other-param)

4.4.5.  Poll-properties

   Property name
      POLL-PROPERTIES

   Purpose
      This property is used in VPOLL to define which icalendar
      properties are being voted on.

   Property Parameters
      Non-standard or iana parameters can be specified on this property.

   Conformance
      This property MAY be specified in a VPOLL component.

   Description
      This property defines which icalendar properties are significant
      in the voting process.  It may not be clear to voters which
      properties are varying in a significant manner.  Clients may use
      this property to highlight those listed properties.

   Format Definition
      This property is defined by the following notation:



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   pollproperties = "POLL-PROPERTIES" pollpropparams ":"
                text *("," text) CRLF

   pollpropparams = *(";" other-param)

4.4.6.  Poll-Winner

   Property name
      POLL-WINNER

   Purpose
      This property is used in a basic mode VPOLL to indicate which of
      the VPOLL sub-components won.

   Value type
      INTEGER

   Property Parameters
      Non-standard parameters can be specified on this property.

   Conformance
      This property MAY be specified in a VPOLL component.

   Description
      For poll confirmation each child component MUST have a POLL-ITEM-
      ID property.  For basic mode the VPOLL component SHOULD have a
      POLL-WINNER property which MUST correspond to one of the POLL-
      ITEM-ID properties and indicates which sub-component was the
      winner.

   Format Definition
      This property is defined by the following notation:

   pollwinner = "POLL-WINNER" pollwinnerparams ":"
                    integer CRLF

   pollwinnerparams = *(";" other-param)

          ; Used with a STATUS:CONFIRMED VPOLL to indicate which
          ; components have been confirmed

4.4.7.  Reply-URL

   Property name
      REPLY-URL

   Purpose




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      This property may be used in scheduling messages to indicate
      additional reply methods, for example a web-service.

   Property Parameters
      Non-standard, required or iana parameters can be specified on this
      property.

   Conformance
      This property MAY be specified in a VPOLL component.

   Description
      When used in a scheduling message this property indicates
      additional or required services that can be used to reply.
      Typically this would be a web service of some form.

   Format Definition
      This property is defined by the following notation:

   reply-url = "REPLY-URL" reply-urlparams ":" uri CRLF

   reply-urlparams = *(
                     (";" requiredparam) /
                     (";" other-param)
                     )

4.4.8.  Response

   Property name
      RESPONSE

   Purpose
      To specify a response vote.

   Value type
      INTEGER

   Format Definition
      This property is defined by the following notation:

   response = "RESPONSE" response-params ":" integer CRLF
                    ; integer value 0..100

   responseparams = *(";" other-param)

   Description
      This parameter can be specified on the POLL-ITEM-ID property to
      provide the value of the voters response.  This parameter allows
      for fine grained responses which are appropriate to some



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      applications.  For the case of individuals voting for a choice of
      events, client applications SHOULD conform to the following
      convention:


      *  0 - 39 A "NO vote"

      *  40 - 79 A "MAYBE" vote

      *  80 - 89 A "YES - but not preferred vote"

      *  90-100 A "YES" vote.
         Clients MUST preserve the response value when there is no
         change from the user even if they have a UI with fixed states
         (e.g.  yes/no/maybe).

4.4.9.  Voter

   Property name
      VOTER

   Purpose
      This property is used in VVOTER components to indicate recipients
      of the poll and to identify that component as containing the
      voters responses.

   Value type
      The value type for this property is cal-address.

   Property Parameters
      Non-standard, cutype, member, role, rsvp, delto, delfrom, sentby,
      cn, dir, lang or stayinformed parameters can be specified on this
      property.

   Conformance
      This property MAY be specified in a VPOLL component or its sub-
      components.

   Description
      This property appears in the VVOTER component only and indicates a
      recipient of the poll and their responses.

   Format Definition
      This property is defined by the following notation:







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   voter = "VOTER" voterparams ":" cal-address CRLF

   voterparam   = *(
                ;
                ; The following are OPTIONAL,
                ; but MUST NOT occur more than once.
                ;
                (";" cutypeparam) / (";" memberparam) /
                (";" roleparam) /
                (";" rsvpparam) / (";" deltoparam) /
                (";" delfromparam) / (";" sentbyparam) /
                (";" cnparam) / (";" dirparam) /
                (";" languageparam) /
                (";" stayinformedparam) /

                ;
                ; The following are OPTIONAL, but MUST NOT occur
                ; more than once. They are defined in RFC6638
                ;
                (";" scheduleagentparam) /
                (";" scheduleforcesendparam) /
                (";" schedulestatusparam) /

                ;
                ; The following is OPTIONAL,
                ; and MAY occur more than once.
                ;
                (";" other-param)
                ;
             )

   Note 1
      "RSVP=TRUE" MAY be used by the organizer to force the voter to
      reset their state and re-vote.

   Note 2
      "scheduleagentparam", "scheduleforcesendparam" and
      "schedulestatusparam" are all related to CalDAV scheduling and are
      defined in [RFC6638].  Their semantics are exactly as defined in
      that specification.

4.5.  New Components

4.5.1.  VPOLL Component

   Component name
      VPOLL




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   Purpose
      This component provides a mechanism by which voters can vote on
      provided choices.

   Format Definition
      This property is defined by the following notation:













































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   pollc    = "BEGIN" ":" "VPOLL" CRLF
               pollprop
               *voterc *eventc *todoc *journalc *freebusyc
               *availabilityc *alarmc *iana-comp *x-comp
               "END" ":" "VPOLL" CRLF

   pollprop = *(
             ;
             ; The following are REQUIRED,
             ; but MUST NOT occur more than once.
             ;
             dtstamp / uid / organizer /
             ;
             ; The following are OPTIONAL,
             ; but MUST NOT occur more than once.
             ;
             acceptresponse / class / created / completed /
             description / dtstart / last-mod / pollmode /
             pollproperties / priority / seq / status /
             summary / url /
             ;
             ; Either 'dtend' or 'duration' MAY appear in
             ; a 'pollprop', but 'dtend' and 'duration'
             ; MUST NOT occur in the same 'pollprop'.
             ; 'duration' MUST only occur when 'dtstart'
             ; is present
             ;
             dtend / duration /
             ;
             ; The following are OPTIONAL,
             ; and MAY occur more than once.
             ;
             attach / categories / comment /
             contact / rstatus / related /
             resources / x-prop / iana-prop
             ;
             ; The following is OPTIONAL, it SHOULD appear
             ; once for the confirmation of a BASIC mode
             ; VPOLL. Other modes may define differing
             ; requirements.
             ;
             pollwinner /
             ;
             )

   Description





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      This component provides a mechanism by which voters can vote on
      provided choices.  The outcome depends upon the POLL-MODE in
      effect.

      The VVOTER components in VPOLL requests provide information on
      each recipient who will be voting - both their identity through
      the VOTER property and their votes through the VOTE components.

      If specified, the "DTSTART" property defines the start or opening
      of the poll active period.  If absent the poll is presumed to have
      started when created.

      If "DTSTART" is present "DURATION" MAY be specified and indicates
      the duration, and hence the ending, of the poll.  The value of the
      property MUST be a positive duration.

      "DTEND" MAY be specified with or without "DTSTART" and indicates
      the ending of the poll.  If DTEND is specified it MUST be later
      than the DTSTART or CREATED property.

      If one or more VALARM components are included in the VPOLL they
      are not components to be voted on and MUST NOT contain a POLL-
      ITEM-ID property.  VALARM sub-components may be used to provide
      warnings to the user when polls are due to start or end.

   TODO: Need some text to describe what relative alarms are relative
   to.

4.5.2.  VVOTER Component

   Component name
      VPOLL

   Purpose
      This component contains identification of the recipient and voter
      and their responses.

   Format Definition
      This property is defined by the following notation:












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   voterc   = "BEGIN" ":" "VVOTER" CRLF
              voterprop
              *votec *iana-comp *x-comp
              "END" ":" "VVOTER" CRLF

   voterprop = *(
              ;
              ; The following are REQUIRED,
              ; but MUST NOT occur more than once.
              ;
              dtstamp  / voter /
              ;
              ; The following are OPTIONAL,
              ; but MUST NOT occur more than once.
              ;
              created / description / last-mod / seq /
              status / summary / url /
              ;
              ; The following are OPTIONAL,
              ; and MAY occur more than once.
              ;
              attach / categories / comment /
              contact / rstatus / related /
              resources / x-prop / iana-prop
              ;
              )

   Description
      This component contains a VOTER property identifying a recipient
      and voter and zero or more VOTE components containing their
      responses.

      The VOTER property in VVOTER objects refers to a recipient who
      will be voting - RSVP=TRUE is used by the organizer to force the
      voter to reset their state and re-vote

4.5.3.  VOTE Component

   Component name
      VPOLL

   Purpose
      This component provides a mechanism by which voters can vote on
      provided choices.

   Format Definition
      This property is defined by the following notation:




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   votec     = "BEGIN" ":" "VOTE" CRLF
               voteprop
               *eventc *todoc *journalc *freebusyc
               *availabilityc *alarmc *iana-comp *x-comp
               "END" ":" "VOTE" CRLF

   voteprop = *(
              ;
              ; The following are REQUIRED,
              ; but MUST NOT occur more than once.
              ;
              pollitemid / response /
              ;
              ; The following are OPTIONAL,
              ; and MAY occur more than once.
              ;
              comment / x-prop / iana-prop
              ;
              )

   Description
      This component identifies voters and contains their responses.

      The required and optional properties and their meanings depend
      upon the POLL-MODE in effect.

      For any POLL-MODE, POLL-ITEM-ID is used to associate the
      information to a choice supplied by the organizer.

      If allowed by the POLL-MODE a VOTE component without a POLL-ITEM-
      ID may be provided in a REPLY to indicate a possible new choice or
      to provide information to the ORGANIZER - such as the respondees
      availability.

5.  Poll Modes

   The VPOLL component is intended to allow for various forms of
   polling.  The particular form in efffect is indicated by the POLL-
   MODE property.

   New poll modes can be registered by including a completed POLL-MODE
   Registration Template (see Section 9.3) in a published RFC.

5.1.  POLL-MODE:BASIC

   BASIC poll mode is the form of voting in which one possible outcome
   is chosen from a set of possibilities.  Usually this will be




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   represented as a number of possible event objects one of which will
   be selected.

5.1.1.  Property restrictions

   This poll mode has the following property requirements:

   POLL-ITEM-ID
      Each contained sub-component that is being voted upon MUST contain
      a POLL-ITEM_ID property which is unique within the context of the
      POLL.  The value MUST NOT be reused when events are removed and/or
      added to the poll.

   POLL-WINNER
      On confirmation of the poll this property MUST be present and
      identifies the winning component.

5.1.2.  Outcome reporting

   To confirm the winner the POLL-WINNER property MUST be present and
   the STATUS MUST be set to CONFIRMED.

   When the winning VEVENT or VTODO is not a scheduled entity, that is,
   it has no ORGANIZER or ATTENDEES it MUST be assigned an ORGANIZER
   property and a list of non-participating ATTENDEEs.  This allows the
   winning entity to be distributed to the participants through iTip or
   some other protocol.

6.  iTIP Extensions

   This specification introduces a number of extensions to [RFC5546].
   In group scheduling the parties involved are organizer and attendees.
   In VPOLL the parties are organizer and voters.

   For many of the iTip processing rules the voters take the place of
   attendees.

6.1.  Methods

   There are some extensions to the behavior of iTip methods for a VPOLL
   object and two new methods are defined.










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   +----------------+--------------------------------------------------+
   | Method         | Description                                      |
   +----------------+--------------------------------------------------+
   | PUBLISH        | No changes (yet)                                 |
   | REQUEST        | Each child component MUST have a POLL-ITEM-ID    |
   |                | property.  Each set of components with the same  |
   |                | POLL-ITEM-ID value represents one overall set of |
   |                | items to be voted on.                            |
   | REPLY          | There MUST be a single VPOLL component which     |
   |                | MUST have: either one or more POLL-ITEM-ID       |
   |                | properties with a RESPONSE param matching that   |
   |                | from a REQUEST or a VFREEBUSY or VAVAILABILITY   |
   |                | child component showing overall busy/available   |
   |                | time. The VPOLL MUST have one VOTER only.        |
   | ADD            | Not supported for VPOLL.                         |
   | CANCEL         | There MUST be a single VPOLL component with UID  |
   |                | matching that of the poll being cancelled.       |
   | REFRESH        | The organizer returns a METHOD:REQUEST with the  |
   |                | current full state, or a METHOD:CANCEL or an     |
   |                | error if no matching poll is found.              |
   | COUNTER        | Not supported for VPOLL.                         |
   | DECLINECOUNTER | Not supported for VPOLL.                         |
   | POLLSTATUS     | Used to send the current state of the poll to    |
   |                | all voters. The VPOLL can contain a reduced set  |
   |                | of properties but MUST contain DTSTAMP, SEQUENCE |
   |                | (if not 0), UID, ORGANIZER and VOTER.            |
   +----------------+--------------------------------------------------+

   The following table shows the above methods broken down by who can
   send them with VPOLL components.

      +------------+------------------------------------------------+
      | Originator | Methods                                        |
      +------------+------------------------------------------------+
      | Organizer  | CANCEL, PUBLISH, REQUEST, POLLSTATUS           |
      | Voter      | REPLY, REFRESH, REQUEST (only when delegating) |
      +------------+------------------------------------------------+

6.2.  Interoperability Models

   Most of the standard iTip specification applies with respect to
   organizer and voters.

6.2.1.  Delegation

   TBD





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6.2.2.  Acting on Behalf of Other Calendar Users

   TBD

6.2.3.  Component Revisions

   o  Need to talk about what a change in SEQUENCE means

   o  Sequence change forces a revote.

   o  New voter - no sequence change

   o  Add another poll set or change poll item ids or any change to a
      child

   o  component - bump sequence

6.2.4.  Message Sequencing

   TBD

6.3.  Application Protocol Elements

6.3.1.  Methods for VPOLL Calendar Components

   This section defines the property set restrictions for the method
   types that are applicable to the "VPOLL" calendar component.  Each
   method is defined using a table that clarifies the property
   constraints that define the particular method.

   The presence column uses the following values to assert whether a
   property is required or optional, and the number of times it may
   appear in the iCalendar object.

   +----------------+--------------------------------------------------+
   | Presence Value | Description                                      |
   +----------------+--------------------------------------------------+
   | 1              | One instance MUST be present.                    |
   | 1+             | At least one instance MUST be present.           |
   | 0              | Instances of this property MUST NOT be present.  |
   | 0+             | Multiple instances MAY be present.               |
   | 0 or 1         | Up to 1 instance of this property MAY be         |
   |                | present.                                         |
   +----------------+--------------------------------------------------+

   The following summarizes the methods that are defined for the "VPOLL"
   calendar component.




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   +------------+------------------------------------------------------+
   | Method     | Description                                          |
   +------------+------------------------------------------------------+
   | PUBLISH    | Post notification of an poll. Used primarily as a    |
   |            | method of advertising the existence of a poll.       |
   | REQUEST    | To make a request for a poll. This is an explicit    |
   |            | invitation to one or more voters. Poll requests are  |
   |            | also used to update, change or confirm an existing   |
   |            | poll. Clients that cannot handle REQUEST MAY degrade |
   |            | the poll to view it as a PUBLISH. REQUEST SHOULD NOT |
   |            | be used just to set the status of the poll -         |
   |            | POLLSTATUS provides a more compact approach.         |
   | REPLY      | Reply to a poll request. Voters may set their        |
   |            | RESPONSE parameter to supply the current vote in the |
   |            | range 0 to 100.                                      |
   | CANCEL     | Cancel a poll.                                       |
   | REFRESH    | A request is sent to an Organizer by a Voter asking  |
   |            | for the latest version of a poll to be resent to the |
   |            | requester.                                           |
   | POLLSTATUS | Used to send the current state of the poll to all    |
   |            | voters. The VPOLL can contain a reduced set of       |
   |            | properties but MUST contain DTSTAMP, SEQUENCE (if    |
   |            | not 0), UID, ORGANIZER and VOTER.                    |
   +------------+------------------------------------------------------+

6.3.2.  Method: PUBLISH

   The "PUBLISH" method in a "VPOLL" calendar component is an
   unsolicited posting of an iCalendar object.  Any CU may add published
   components to their calendar.  The "Organizer" MUST be present in a
   published iCalendar component.  "Voters" MUST NOT be present.  Its
   expected usage is for encapsulating an arbitrary poll as an iCalendar
   object.  The "Organizer" may subsequently update (with another
   "PUBLISH" method) or cancel (with a "CANCEL" method) a previously
   published "VPOLL" calendar component.

   This method type is an iCalendar object that conforms to the
   following property constraints:

   +--------------------+----------+-----------------------------------+
   | Component/Property | Presence | Comment                           |
   +--------------------+----------+-----------------------------------+
   | METHOD             | 1        | MUST equal PUBLISH.               |
   | VPOLL              | 1+       |                                   |
   | DTSTAMP            | 1        |                                   |
   | DTSTART            | 0 or 1   | If present defines the start of   |
   |                    |          | the poll. Otherwise the poll      |
   |                    |          | starts when it is created and     |



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   |                    |          | distributed.                      |
   | ORGANIZER          | 1        |                                   |
   | SUMMARY            | 1        | Can be null.                      |
   | UID                | 1        |                                   |
   | SEQUENCE           | 0 or 1   | MUST be present if value is       |
   |                    |          | greater than 0; MAY be present if |
   |                    |          | 0.                                |
   | ACCEPT-RESPONSE    | 0 or 1   |                                   |
   | ATTACH             | 0+       |                                   |
   | CATEGORIES         | 0+       |                                   |
   | CLASS              | 0 or 1   |                                   |
   | COMMENT            | 0+       |                                   |
   | COMPLETED          | 0 or 1   |                                   |
   | CONTACT            | 0 or 1   |                                   |
   | CREATED            | 0 or 1   |                                   |
   | DESCRIPTION        | 0 or 1   | Can be null.                      |
   | DTEND              | 0 or 1   | If present, DURATION MUST NOT be  |
   |                    |          | present.                          |
   | DURATION           | 0 or 1   | If present, DTEND MUST NOT be     |
   |                    |          | present.                          |
   | LAST-MODIFIED      | 0 or 1   |                                   |
   | POLL-ITEM-ID       | 0        |                                   |
   | POLL-MODE          | 0 or 1   |                                   |
   | POLL-PROPERTIES    | 0 or 1   |                                   |
   | PRIORITY           | 0 or 1   |                                   |
   | RELATED-TO         | 0+       |                                   |
   | RESOURCES          | 0+       |                                   |
   | STATUS             | 0 or 1   | MAY be one of                     |
   |                    |          | COMPLETED/CONFIRMED/CANCELLED.    |
   | URL                | 0 or 1   |                                   |
   | IANA-PROPERTY      | 0+       |                                   |
   | X-PROPERTY         | 0+       |                                   |
   | VOTER              | 0        |                                   |
   | REQUEST-STATUS     | 0        |                                   |
   | VALARM             | 0+       |                                   |
   | VEVENT             | 0+       | Depending upon the poll mode in   |
   |                    |          | effect there MAY be candidate     |
   |                    |          | components included in the poll   |
   |                    |          | component. If voting has already  |
   |                    |          | taken place, these components     |
   |                    |          | MUST include the VOTER property   |
   |                    |          | to indicate each voters current   |
   |                    |          | response.                         |
   | VFREEBUSY          | 0        |                                   |
   | VJOURNAL           | 0+       | Depending upon the poll mode in   |
   |                    |          | effect there MAY be candidate     |
   |                    |          | components included in the poll   |
   |                    |          | component. If voting has already  |



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   |                    |          | taken place, these components     |
   |                    |          | MUST include the VOTER property   |
   |                    |          | to indicate each voters current   |
   |                    |          | response.                         |
   | VTODO              | 0+       | Depending upon the poll mode in   |
   |                    |          | effect there MAY be candidate     |
   |                    |          | components included in the poll   |
   |                    |          | component. If voting has already  |
   |                    |          | taken place, these components     |
   |                    |          | MUST include the VOTER property   |
   |                    |          | to indicate each voters current   |
   |                    |          | response.                         |
   | VTIMEZONE          | 0+       | MUST be present if any date/time  |
   |                    |          | refers to a timezone.             |
   | IANA-COMPONENT     | 0+       |                                   |
   | X-COMPONENT        | 0+       |                                   |
   +--------------------+----------+-----------------------------------+

                Constraints for a METHOD:PUBLISH of a VPOLL

6.3.3.  Method: REQUEST

   The "REQUEST" method in a "VPOLL" component provides the following
   scheduling functions:

   o  Invite "Voters" to respond to the poll.

   o  Change the items being voted upon.

   o  Complete or confirm the poll.

   o  Response to a "REFRESH" request.

   o  Update the details of an existing vpoll.

   o  Update the status of "Voters".

   o  Forward a "VPOLL" to another uninvited CU.

   o  For an existing "VPOLL" calendar component, delegate the role of
      "Voter" to another CU.

   o  For an existing "VPOLL" calendar component, change the role of
      "Organizer" to another CU.

   The "Organizer" originates the "REQUEST".  The recipients of the
   "REQUEST" method are the CUs voting in the poll, the "Voters".
   "Voters" use the "REPLY" method to convey votes to the "Organizer".



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   The "UID" and "SEQUENCE" properties are used to distinguish the
   various uses of the "REQUEST" method.  If the "UID" property value in
   the "REQUEST" is not found on the recipient's calendar, then the
   "REQUEST" is for a new "VPOLL" calendar component.  If the "UID"
   property value is found on the recipient's calendar, then the
   "REQUEST" is for an update, or a reconfirmation of the "VPOLL"
   calendar component.

   For the "REQUEST" method only a single iCalendar object is permitted.

   This method type is an iCalendar object that conforms to the
   following property constraints:

   +--------------------+----------+-----------------------------------+
   | Component/Property | Presence | Comment                           |
   +--------------------+----------+-----------------------------------+
   | METHOD             | 1        | MUST be REQUEST.                  |
   | VPOLL              | 1        |                                   |
   | VOTER              | 1+       |                                   |
   | DTSTAMP            | 1        |                                   |
   | DTSTART            | 0 or 1   | If present defines the start of   |
   |                    |          | the poll. Otherwise the poll      |
   |                    |          | starts when it is created and     |
   |                    |          | distributed.                      |
   | ORGANIZER          | 1        |                                   |
   | SEQUENCE           | 0 or 1   | MUST be present if value is       |
   |                    |          | greater than 0; MAY be present if |
   |                    |          | 0.                                |
   | SUMMARY            | 1        | Can be null.                      |
   | UID                | 1        |                                   |
   | ACCEPT-RESPONSE    | 0 or 1   |                                   |
   | ATTACH             | 0+       |                                   |
   | CATEGORIES         | 0+       |                                   |
   | CLASS              | 0 or 1   |                                   |
   | COMMENT            | 0+       |                                   |
   | COMPLETED          | 0 or 1   |                                   |
   | CONTACT            | 0+       |                                   |
   | CREATED            | 0 or 1   |                                   |
   | DESCRIPTION        | 0 or 1   | Can be null.                      |
   | DTEND              | 0 or 1   | If present, DURATION MUST NOT be  |
   |                    |          | present.                          |
   | DURATION           | 0 or 1   | If present, DTEND MUST NOT be     |
   |                    |          | present.                          |
   | GEO                | 0 or 1   |                                   |
   | LAST-MODIFIED      | 0 or 1   |                                   |
   | LOCATION           | 0 or 1   |                                   |
   | POLL-ITEM-ID       | 0        |                                   |
   | POLL-MODE          | 0 or 1   |                                   |



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   | POLL-PROPERTIES    | 0 or 1   |                                   |
   | PRIORITY           | 0 or 1   |                                   |
   | RELATED-TO         | 0+       |                                   |
   | REQUEST-STATUS     | 0        |                                   |
   | RESOURCES          | 0+       |                                   |
   | STATUS             | 0 or 1   | MAY be one of                     |
   |                    |          | COMPLETED/CONFIRMED/CANCELLED.    |
   | TRANSP             | 0 or 1   |                                   |
   | URL                | 0 or 1   |                                   |
   | IANA-PROPERTY      | 0+       |                                   |
   | X-PROPERTY         | 0+       |                                   |
   | VALARM             | 0+       |                                   |
   | VTIMEZONE          | 0+       | MUST be present if any date/time  |
   |                    |          | refers to a timezone.             |
   | IANA-COMPONENT     | 0+       |                                   |
   | X-COMPONENT        | 0+       |                                   |
   | VEVENT             | 0+       | Depending upon the poll mode in   |
   |                    |          | effect there MAY be candidate     |
   |                    |          | components included in the poll   |
   |                    |          | component. If voting has already  |
   |                    |          | taken place, these components     |
   |                    |          | MUST include the VOTER property   |
   |                    |          | to indicate each voters current   |
   |                    |          | response.                         |
   | VFREEBUSY          | 0        |                                   |
   | VJOURNAL           | 0+       | Depending upon the poll mode in   |
   |                    |          | effect there MAY be candidate     |
   |                    |          | components included in the poll   |
   |                    |          | component. If voting has already  |
   |                    |          | taken place, these components     |
   |                    |          | MUST include the VOTER property   |
   |                    |          | to indicate each voters current   |
   |                    |          | response.                         |
   | VTODO              | 0+       | Depending upon the poll mode in   |
   |                    |          | effect there MAY be candidate     |
   |                    |          | components included in the poll   |
   |                    |          | component. If voting has already  |
   |                    |          | taken place, these components     |
   |                    |          | MUST include the VOTER property   |
   |                    |          | to indicate each voters current   |
   |                    |          | response.                         |
   +--------------------+----------+-----------------------------------+

                Constraints for a METHOD:REQUEST of a VPOLL







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6.3.3.1.  Rescheduling a poll

   The "REQUEST" method may be used to reschedule a poll, that is force
   a revote.  A rescheduled poll involves a change to the existing poll
   in terms of its time the components being voted on may have changed.
   If the recipient CUA of a "REQUEST" method finds that the "UID"
   property value already exists on the calendar but that the "SEQUENCE"
   (or "DTSTAMP") property value in the "REQUEST" method is greater than
   the value for the existing poll, then the "REQUEST" method describes
   a rescheduling of the poll.

6.3.3.2.  Updating or Reconfirmation of a Poll

   The "REQUEST" method may be used to update or reconfirm a poll.  An
   update to an existing poll does not involve changes to the time or
   candidates, and might not involve a change to the location or
   description for the poll.  If the recipient CUA of a "REQUEST" method
   finds that the "UID" property value already exists on the calendar
   and that the "SEQUENCE" property value in the "REQUEST" is the same
   as the value for the existing poll, then the "REQUEST" method

   describes an update of the poll details, but not a rescheduling of
   the POLL.

   The update "REQUEST" method is the appropriate response to a
   "REFRESH" method sent from a "Voter" to the "Organizer" of a poll.

   The "Organizer" of a poll may also send unsolicited "REQUEST"
   methods.  The unsolicited "REQUEST" methods may be used to update the
   details of the poll without rescheduling it, to update the "RESPONSE"
   parameter of "Voters", or to reconfirm the poll.

6.3.3.3.  Confirmation of a Poll

   The "REQUEST" method may be used to confirm a poll, that is announce
   the winner in BASIC mode.  The STATUS MUST be set to CONFIRMED and
   for BASIC mode a VPOLL POLL-WINNER property must be provided with the
   poll-id of the winning component.

6.3.3.4.  Closing a Poll

   The "REQUEST" method may be used to close a poll, that is indicate
   voting is completed.  The STATUS MUST be set to COMPLETED.








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6.3.3.5.  Delegating a Poll to Another CU

   Some calendar and scheduling systems allow "Voters" to delegate the
   vote to another "Calendar User". iTIP supports this concept using the
   following workflow.  Any "Voter" may delegate their right to vote in
   a poll to another CU.  The implication is that the delegate
   participates in lieu of the original "Voter", NOT in addition to the
   "Voter".  The delegator MUST notify the "Organizer" of this action
   using the steps outlined below.  Implementations may support or
   restrict delegation as they see fit.  For instance, some
   implementations may restrict a delegate from delegating a "REQUEST"
   to another CU.

   The "Delegator" of a poll forwards the existing "REQUEST" to the
   "Delegate".  The "REQUEST" method MUST include a "Voter" property
   with the calendar address of the "Delegate".  The "Delegator" MUST
   also send a "REPLY" method to the "Organizer" with the "Delegator's"
   "Voter" property "DELEGATED-TO" parameter set to the calendar address
   of the "Delegate".  Also, a new "Voter" property for the "Delegate"
   MUST be included and must specify the calendar user address set in
   the "DELEGATED-TO" parameter, as above.

   In response to the request, the "Delegate" MUST send a "REPLY" method
   to the "Organizer", and optionally to the "Delegator".  The "REPLY"

   method SHOULD include the "Voter" property with the "DELEGATED-FROM"
   parameter value of the "Delegator's" calendar address.

   The "Delegator" may continue to receive updates to the poll even
   though they will not be attending.  This is accomplished by the
   "Delegator" setting their "role" attribute to "NON-PARTICIPANT" in
   the "REPLY" to the "Organizer".

6.3.3.6.  Changing the Organizer

   The situation may arise where the "Organizer" of a "VPOLL" is no
   longer able to perform the "Organizer" role and abdicates without
   passing on the "Organizer" role to someone else.  When this occurs,
   the "Voters" of the "VPOLL" may use out-of-band mechanisms to
   communicate the situation and agree upon a new "Organizer".  The new
   "Organizer" should then send out a new "REQUEST" with a modified
   version of the "VPOLL" in which the "SEQUENCE" number has been
   incremented and the "ORGANIZER" property has been changed to the new
   "Organizer".







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6.3.3.7.  Sending on Behalf of the Organizer

   There are a number of scenarios that support the need for a "Calendar
   User" to act on behalf of the "Organizer" without explicit role
   changing.  This might be the case if the CU designated as "Organizer"
   is sick or unable to perform duties associated with that function.
   In these cases, iTIP supports the notion of one CU acting on behalf
   of another.  Using the "SENT-BY" parameter, a "Calendar User" could
   send an updated "VPOLL" "REQUEST".  In the case where one CU sends on
   behalf of another CU, the "Voter" responses are still directed back
   towards the CU designated as "Organizer".

6.3.3.8.  Forwarding to an Uninvited CU

   A "Voter" invited to a "VPOLL" calendar component may send the
   "VPOLL" calendar component to another new CU not previously
   associated with the "VPOLL" calendar component.  The current "Voter"
   participating in the "VPOLL" calendar component does this by
   forwarding the original "REQUEST" method to the new CU.  The new CU
   can send a "REPLY" to the "Organizer" of the "VPOLL" calendar
   component.  The reply contains a "Voter" property for the new CU.

   The "Organizer" ultimately decides whether or not the new CU becomes
   part of the poll and is not obligated to do anything with a "REPLY"
   from a new (uninvited) CU.  If the "Organizer" does not want the new
   CU to be part of the poll, the new "Voter" property is not added to
   the "VPOLL" calendar component.  The "Organizer" MAY send the CU a
   "CANCEL" message to indicate that they will not be added to the poll.

   If the "Organizer" decides to add the new CU, the new "Voter"
   property is added to the "VPOLL" calendar component.  Furthermore,
   the "Organizer" is free to change any "Voter" property parameter from
   the values supplied by the new CU to something the "Organizer"
   considers appropriate.  The "Organizer" SHOULD send the new CU a
   "REQUEST" message to inform them that they have been added.

   When forwarding a "REQUEST" to another CU, the forwarding "Voter"
   MUST NOT make changes to the original message.

6.3.3.9.  Updating Voter Status

   The "Organizer" of an poll may also request updated status from one
   or more "Voters".  The "Organizer" sends a "REQUEST" method to the
   "Voter" and sets the "VOTER;RSVP=TRUE" property parameter.  The
   "SEQUENCE" property for the poll is not changed from its previous
   value.  A recipient will determine that the only change in the
   "REQUEST" is that their "RSVP" property parameter indicates a request




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   for updated status.  The recipient SHOULD respond with a "REPLY"
   method indicating their current vote with respect to the "REQUEST".

6.3.4.  Method: REPLY

   The "REPLY" method in a "VPOLL" calendar component is used to respond
   (e.g., accept or decline) to a "REQUEST" or to reply to a delegation
   "REQUEST".  When used to provide a delegation response, the
   "Delegator" SHOULD include the calendar address of the "Delegate" on
   the "DELEGATED-TO" property parameter of the "Delegator's" "Voter"
   property.  The "Delegate" SHOULD include the calendar address of the
   "Delegator" on the "DELEGATED-FROM" property parameter of the
   "Delegate's" "Voter" property.

   The "REPLY" method is also used when processing of a "REQUEST" fails.
   Depending on the value of the "REQUEST-STATUS" property, no action
   may have been performed.

   The "Organizer" of a poll may receive the "REPLY" method from a CU
   not in the original "REQUEST".  For example, a "REPLY" may be
   received from a "Delegate" to a poll.  In addition, the "REPLY"
   method may be received from an unknown CU (a "Party Crasher").  This
   uninvited "Voter" may be accepted, or the "Organizer" may cancel the
   poll for the uninvited "Voter" by sending a "CANCEL" method to the
   uninvited "Voter".

   A "Voter" MAY include a message to the "Organizer" using the
   "COMMENT" property.  For example, if the user indicates a low
   interest and wants to let the "Organizer" know why, the reason can be
   expressed in the "COMMENT" property value.

   The "Organizer" may also receive a "REPLY" from one CU on behalf of
   another.  Like the scenario enumerated above for the "Organizer",
   "Voters" may have another CU respond on their behalf.  This is done
   using the "SENT-BY" parameter.

   The optional properties listed in the table below (those listed as
   "0+" or "0 or 1") MUST NOT be changed from those of the original
   request.  (But see comments on VFREEBUSY and VAVAILABILITY)

   This method type is an iCalendar object that conforms to the
   following property constraints:

   +--------------------+----------+-----------------------------------+
   | Component/Property | Presence | Comment                           |
   +--------------------+----------+-----------------------------------+
   | METHOD             | 1        | MUST be REPLY.                    |
   | VPOLL              | 1+       | All components MUST have the same |



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   |                    |          | UID.                              |
   | VOTER              | 1        | MUST be the address of the Voter  |
   |                    |          | replying.                         |
   | DTSTAMP            | 1        |                                   |
   | ORGANIZER          | 1        |                                   |
   | UID                | 1        | MUST be the UID of the original   |
   |                    |          | REQUEST.                          |
   | SEQUENCE           | 0 or 1   | If non-zero, MUST be the sequence |
   |                    |          | number of the original REQUEST.   |
   |                    |          | MAY be present if 0.              |
   | ACCEPT-RESPONSE    | 0 or 1   |                                   |
   | ATTACH             | 0+       |                                   |
   | CATEGORIES         | 0+       |                                   |
   | CLASS              | 0 or 1   |                                   |
   | COMMENT            | 0+       |                                   |
   | COMPLETED          | 0 or 1   |                                   |
   | CONTACT            | 0+       |                                   |
   | CREATED            | 0 or 1   |                                   |
   | DESCRIPTION        | 0 or 1   |                                   |
   | DTEND              | 0 or 1   | If present, DURATION MUST NOT be  |
   |                    |          | present.                          |
   | DTSTART            | 0 or 1   |                                   |
   | DURATION           | 0 or 1   | If present, DTEND MUST NOT be     |
   |                    |          | present.                          |
   | GEO                | 0 or 1   |                                   |
   | LAST-MODIFIED      | 0 or 1   |                                   |
   | LOCATION           | 0 or 1   |                                   |
   | POLL-ITEM-ID       | 1+       | One per item being voted on.      |
   | POLL-MODE          | 0        |                                   |
   | POLL-PROPERTIES    | 0        |                                   |
   | PRIORITY           | 0 or 1   |                                   |
   | RELATED-TO         | 0+       |                                   |
   | RESOURCES          | 0+       |                                   |
   | REQUEST-STATUS     | 0+       |                                   |
   | STATUS             | 0 or 1   |                                   |
   | SUMMARY            | 0 or 1   |                                   |
   | TRANSP             | 0 or 1   |                                   |
   | URL                | 0 or 1   |                                   |
   | IANA-PROPERTY      | 0+       |                                   |
   | X-PROPERTY         | 0+       |                                   |
   | VALARM             | 0        |                                   |
   | VTIMEZONE          | 0 or 1   | MUST be present if any date/time  |
   |                    |          | refers to a timezone.             |
   | IANA-COMPONENT     | 0+       |                                   |
   | X-COMPONENT        | 0+       |                                   |
   | VEVENT             | 0        |                                   |
   | VFREEBUSY          | 0 or 1   | A voter may respond with a        |
   |                    |          | VFREEBUSY component indicating    |



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   |                    |          | that the ORGANIZER may select     |
   |                    |          | some other time which is not      |
   |                    |          | marked as busy.                   |
   | VAVAILABILITY      | 0        | A voter may respond with a        |
   |                    |          | VAVAILABILITY component           |
   |                    |          | indicating that the ORGANIZER may |
   |                    |          | select some other time which is   |
   |                    |          | shown as available.               |
   | VJOURNAL           | 0        |                                   |
   | VTODO              | 0        |                                   |
   +--------------------+----------+-----------------------------------+

                 Constraints for a METHOD:REPLY of a VPOLL

6.3.5.  Method: CANCEL

   The "CANCEL" method in a "VPOLL" calendar component is used to send a
   cancellation notice of an existing poll request to the affected
   "Voters".  The message is sent by the "Organizer" of the poll.

   The "Organizer" MUST send a "CANCEL" message to each "Voter" affected
   by the cancellation.  This can be done using a single "CANCEL"
   message for all "Voters" or by using multiple messages with different
   subsets of the affected "Voters" in each.

   When a "VPOLL" is cancelled, the "SEQUENCE" property value MUST be
   incremented as described in Section 6.2.3.

   Once a CANCEL message has been sent to all voters no further voting
   may take place.  The poll is considered closed.

   This method type is an iCalendar object that conforms to the
   following property constraints:

   +--------------------+----------+-----------------------------------+
   | Component/Property | Presence | Comment                           |
   +--------------------+----------+-----------------------------------+
   | METHOD             | 1        | MUST be CANCEL.                   |
   | VPOLL              | 1+       | All must have the same UID.       |
   | VOTER              | 0+       | MUST include some or all Voters   |
   |                    |          | being removed from the poll. MUST |
   |                    |          | include some or all Voters if the |
   |                    |          | entire poll is cancelled.         |
   | UID                | 1        | MUST be the UID of the original   |
   |                    |          | REQUEST.                          |
   | DTSTAMP            | 1        |                                   |
   | ORGANIZER          | 1        |                                   |
   | SEQUENCE           | 1        |                                   |



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   | ATTACH             | 0+       |                                   |
   | ACCEPT-RESPONSE    | 0        |                                   |
   | COMMENT            | 0+       |                                   |
   | COMPLETED          | 0 or 1   |                                   |
   | CATEGORIES         | 0+       |                                   |
   | CLASS              | 0 or 1   |                                   |
   | CONTACT            | 0+       |                                   |
   | CREATED            | 0 or 1   |                                   |
   | DESCRIPTION        | 0 or 1   |                                   |
   | DTEND              | 0 or 1   | If present, DURATION MUST NOT be  |
   |                    |          | present.                          |
   | DTSTART            | 0 or 1   |                                   |
   | DURATION           | 0 or 1   | If present, DTEND MUST NOT be     |
   |                    |          | present.                          |
   | GEO                | 0 or 1   |                                   |
   | LAST-MODIFIED      | 0 or 1   |                                   |
   | LOCATION           | 0 or 1   |                                   |
   | POLL-ITEM-ID       | 0        |                                   |
   | POLL-MODE          | 0        |                                   |
   | POLL-PROPERTIES    | 0        |                                   |
   | PRIORITY           | 0 or 1   |                                   |
   | RELATED-TO         | 0+       |                                   |
   | RESOURCES          | 0+       |                                   |
   | STATUS             | 0 or 1   | MUST be set to CANCELLED to       |
   |                    |          | cancel the entire event. If       |
   |                    |          | uninviting specific Attendees,    |
   |                    |          | then MUST NOT be included.        |
   | SUMMARY            | 0 or 1   |                                   |
   | TRANSP             | 0 or 1   |                                   |
   | URL                | 0 or 1   |                                   |
   | IANA-PROPERTY      | 0+       |                                   |
   | X-PROPERTY         | 0+       |                                   |
   | REQUEST-STATUS     | 0        |                                   |
   | VALARM             | 0        |                                   |
   | VTIMEZONE          | 0+       | MUST be present if any date/time  |
   |                    |          | refers to a timezone.             |
   | IANA-COMPONENT     | 0+       |                                   |
   | X-COMPONENT        | 0+       |                                   |
   | VTODO              | 0        |                                   |
   | VJOURNAL           | 0        |                                   |
   | VEVENT             | 0        |                                   |
   | VFREEBUSY          | 0        |                                   |
   +--------------------+----------+-----------------------------------+

                Constraints for a METHOD:CANCEL of a VPOLL






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6.3.6.  Method: REFRESH

   The "REFRESH" method in a "VPOLL" calendar component is used by
   "Voters" of an existing event to request an updated description from
   the poll "Organizer".  The "REFRESH" method must specify the "UID"
   property of the poll to update.  The "Organizer" responds with the
   latest description and version of the poll.

   This method type is an iCalendar object that conforms to the
   following property constraints:

   +--------------------+----------+-----------------------------------+
   | Component/Property | Presence | Comment                           |
   +--------------------+----------+-----------------------------------+
   | METHOD             | 1        | MUST be REFRESH.                  |
   | VPOLL              | 1        |                                   |
   | VOTER              | 1        | MUST be the address of requester. |
   | DTSTAMP            | 1        |                                   |
   | ORGANIZER          | 1        |                                   |
   | UID                | 1        | MUST be the UID associated with   |
   |                    |          | original REQUEST.                 |
   | COMMENT            | 0+       |                                   |
   | COMPLETED          | 0        |                                   |
   | IANA-PROPERTY      | 0+       |                                   |
   | X-PROPERTY         | 0+       |                                   |
   | ACCEPT-RESPONSE    | 0        |                                   |
   | ATTACH             | 0        |                                   |
   | CATEGORIES         | 0        |                                   |
   | CLASS              | 0        |                                   |
   | CONTACT            | 0        |                                   |
   | CREATED            | 0        |                                   |
   | DESCRIPTION        | 0        |                                   |
   | DTEND              | 0        |                                   |
   | DTSTART            | 0        |                                   |
   | DURATION           | 0        |                                   |
   | GEO                | 0        |                                   |
   | LAST-MODIFIED      | 0        |                                   |
   | LOCATION           | 0        |                                   |
   | POLL-ITEM-ID       | 0        |                                   |
   | POLL-MODE          | 0        |                                   |
   | POLL-PROPERTIES    | 0        |                                   |
   | PRIORITY           | 0        |                                   |
   | RELATED-TO         | 0        |                                   |
   | REQUEST-STATUS     | 0        |                                   |
   | RESOURCES          | 0        |                                   |
   | SEQUENCE           | 0        |                                   |
   | STATUS             | 0        |                                   |
   | SUMMARY            | 0        |                                   |



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   | URL                | 0        |                                   |
   | VALARM             | 0        |                                   |
   | VTIMEZONE          | 0+       |                                   |
   | IANA-COMPONENT     | 0+       |                                   |
   | X-COMPONENT        | 0+       |                                   |
   | VTODO              | 0        |                                   |
   | VJOURNAL           | 0        |                                   |
   | VEVENT             | 0        |                                   |
   | VFREEBUSY          | 0        |                                   |
   +--------------------+----------+-----------------------------------+

                Constraints for a METHOD:REFRESH of a VPOLL

6.3.7.  Method: POLLSTATUS

   The "POLLSTATUS" method in a "VPOLL" calendar component is used to
   inform recipients of the current status of the poll in a compact
   manner.  The "Organizer" MUST be present in the confirmed poll
   component.  "Voters" MUST NOT be present.  The selected component(s)
   according to the poll mode MUST also be present in the poll
   component.  Clients receiving this message may store the confirmed
   items in their calendars.

   This method type is an iCalendar object that conforms to the
   following property constraints:

   +--------------------+----------+-----------------------------------+
   | Component/Property | Presence | Comment                           |
   +--------------------+----------+-----------------------------------+
   | METHOD             | 1        | MUST equal POLLSTATUS.            |
   | VPOLL              | 1+       |                                   |
   | COMPLETED          | 0 or 1   | Only present for a completed poll |
   | DTSTAMP            | 1        |                                   |
   | DTSTART            | 0 or 1   |                                   |
   | ORGANIZER          | 1        |                                   |
   | SUMMARY            | 1        | Can be null.                      |
   | VOTER              | 1+       |                                   |
   | UID                | 1        |                                   |
   | SEQUENCE           | 0 or 1   | MUST be present if value is       |
   |                    |          | greater than 0; MAY be present if |
   |                    |          | 0.                                |
   | ACCEPT-RESPONSE    | 0        |                                   |
   | ATTACH             | 0        |                                   |
   | CATEGORIES         | 0        |                                   |
   | CLASS              | 0        |                                   |
   | COMMENT            | 0+       |                                   |
   | CONTACT            | 0        |                                   |
   | CREATED            | 0 or 1   |                                   |



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   | DESCRIPTION        | 0 or 1   | Can be null.                      |
   | DTEND              | 0 or 1   | If present, DURATION MUST NOT be  |
   |                    |          | present.                          |
   | DURATION           | 0 or 1   | If present, DTEND MUST NOT be     |
   |                    |          | present.                          |
   | LAST-MODIFIED      | 0 or 1   |                                   |
   | POLL-ITEM-ID       | 0        |                                   |
   | POLL-MODE          | 0 or 1   |                                   |
   | POLL-PROPERTIES    | 0        |                                   |
   | PRIORITY           | 0 or 1   |                                   |
   | RELATED-TO         | 0+       |                                   |
   | RESOURCES          | 0+       |                                   |
   | STATUS             | 0 or 1   | MAY be one of                     |
   |                    |          | TENTATIVE/CONFIRMED/CANCELLED.    |
   | URL                | 0 or 1   |                                   |
   | IANA-PROPERTY      | 0+       |                                   |
   | X-PROPERTY         | 0+       |                                   |
   | REQUEST-STATUS     | 0        |                                   |
   | VALARM             | 0+       |                                   |
   | VEVENT             | 0+       | All candidate components MUST be  |
   |                    |          | present but in a reduced form     |
   |                    |          | sufficient to provide the voting  |
   |                    |          | status.                           |
   | VFREEBUSY          | 0        |                                   |
   | VJOURNAL           | 0+       | All candidate components MUST be  |
   |                    |          | present but in a reduced form     |
   |                    |          | sufficient to provide the voting  |
   |                    |          | status.                           |
   | VTODO              | 0+       | All candidate components MUST be  |
   |                    |          | present but in a reduced form     |
   |                    |          | sufficient to provide the voting  |
   |                    |          | status.                           |
   | VTIMEZONE          | 0+       | MUST be present if any date/time  |
   |                    |          | refers to a timezone.             |
   | IANA-COMPONENT     | 0+       |                                   |
   | X-COMPONENT        | 0+       |                                   |
   +--------------------+----------+-----------------------------------+

              Constraints for a METHOD:POLLSTATUS of a VPOLL

7.  CalDAV Extensions

   This specification extends [RFC4791] in that it defines a new
   component and new iCalendar properties to be supported and requires
   extra definitions related to time-ranges and reports.

   Additionally, it extends [RFC6638] as it a VPOLL component is a
   schedulable entity.



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7.1.  Calendar Collection Properties

   This section defines new CalDAV properties for calendar collections.

7.1.1.  CALDAV:supported-vpoll-component-sets

   Name
      supported-vpoll-component-sets

   Namespace
      urn:ietf:params:xml:ns:caldav

   Purpose
      Specifies the calendar component types (e.g., VEVENT, VTODO, etc.)
      and combination of types that may be included in a VPOLL
      component.

   Conformance
      This property MAY be defined on any calendar collection.  If
      defined, it MUST be protected and SHOULD NOT be returned by a
      PROPFIND DAV:allprop request (as defined in section=12.14.1
      [RFC2518]).

   Description
      The CALDAV:supported-vpoll-component-sets property is used to
      specify restrictions on the calendar component types that VPOLL
      components may contain in a calendar collection.

      It also specifies the combination of allowed component types.

      Any attempt by the client to store VPOLL components with component
      types or combinations of types not listed in this property, if it
      exists, MUST result in an error, with the "CALDAV:supported-vpoll-
      component-sets" precondition Section 7.2 being violated.  Since
      this property is protected, it cannot be changed by clients using
      a PROPPATCH request.  However, clients can initialize the value of
      this property when creating a new calendar collection with
      MKCALENDAR.  In the absence of this property, the server MUST
      accept all component types, and the client can assume that all
      component types are accepted.

   Definition

   <!ELEMENT supported-vpoll-component-sets
        (supported-vpoll-component-set*) >

   <!ELEMENT supported-vpoll-component-set (comp+)>




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   <C:supported-vpoll-component-sets
        xmlns:C="urn:ietf:params:xml:ns:caldav">

     <!-- VPOLLs with VEVENT, VFREEBUSY or VTODO -->
     <C:supported-vpoll-component-set>
       <C:comp name="VEVENT" />
       <C:comp name="VFREEBUSY" />
       <C:comp name="VTODO" />
     </C:supported-vpoll-component-set>

     <!-- VPOLLs with just VEVENT or VFREEBUSY -->
     <C:supported-vpoll-component-set>
       <C:comp name="VEVENT" />
       <C:comp name="VFREEBUSY" />
     </C:supported-vpoll-component-set>

     <!-- VPOLLs with just VEVENT -->
     <C:supported-vpoll-component-set>
       <C:comp name="VEVENT" />
     </C:supported-vpoll-component-set>

     <!-- VPOLLs with just VTODO -->
     <C:supported-vpoll-component-set>
       <C:comp name="VTODO" />
     </C:supported-vpoll-component-set>
   </C:supported-vpoll-component-sets>

7.1.2.  CALDAV:vpoll-max-items

   Name
      vpoll-max-items

   Namespace
      urn:ietf:params:xml:ns:caldav

   Purpose
      Provides a numeric value indicating the maximum number of items
      that may be contained in any instance of a VPOLL calendar object
      resource stored in the calendar collection.

   Conformance
      This property MAY be defined on any calendar collection.  If
      defined, it MUST be protected and SHOULD NOT be returned by a
      PROPFIND DAV:allprop request (as defined in section=12.14.1
      [RFC2518]).

   Description




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      The CALDAV:vpoll-max-items is used to specify a numeric value that
      indicates the maximum number of iCalendar components in any one
      instance of a VPOLL calendar object resource stored in a calendar
      collection.  Any attempt to store a calendar object resource with
      more components per instance than this value MUST result in an
      error, with the CALDAV: vpoll-max-items precondition Section 7.2
      being violated.  In the absence of this property, the client can
      assume that the server can handle any number of items in a VPOLL
      calendar component.

   Definition

   <!ELEMENT vpoll-max-items (#PCDATA)>
   PCDATA value: a numeric value (integer greater than zero)

   <C:vpoll-max-items xmlns:C="urn:ietf:params:xml:ns:caldav"
   >25</C:vpoll-max-items>

7.1.3.  CALDAV:vpoll-max-active

   Name
      vpoll-max-active

   Namespace
      urn:ietf:params:xml:ns:caldav

   Purpose
      Provides a numeric value indicating the maximum number of active
      vpolls at any one time.

   Conformance
      This property MAY be defined on any calendar collection.  If
      defined, it MUST be protected and SHOULD NOT be returned by a
      PROPFIND DAV:allprop request (as defined in section=12.14.1
      [RFC2518]).

   Description
      The CALDAV:vpoll-max-active is used to specify a numeric value
      that indicates the maximum number of active VPOLLs at any one
      time.  Any attempt to store a new active VPOLL calendar object
      resource which results in exceeding this limit MUST result in an
      error, with the "CALDAV:vpoll-max-active" precondition Section 7.2
      being violated.  In the absence of this property, the client can
      assume that the server can handle any number of active VPOLLs.

   Definition





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   <!ELEMENT vpoll-max-active (#PCDATA)>
   PCDATA value: a numeric value (integer greater than zero)

   <C:vpoll-max-active xmlns:C="urn:ietf:params:xml:ns:caldav"
   >25</C:vpoll-max-active>

7.1.4.  CALDAV:vpoll-max-voters

   Name
      "vpoll-max-voters"

   Namespace
      "urn:ietf:params:xml:ns:caldav"

   Purpose
      Provides a numeric value indicating the maximum number of voters
      for any instance of a VPOLL calendar object resource stored in the
      calendar collection.

   Conformance
      This property MAY be defined on any calendar collection.  If
      defined, it MUST be protected and SHOULD NOT be returned by a
      PROPFIND "DAV:allprop" request (as defined in section=12.14.1
      [RFC2518]).

   Description
      The "CALDAV:vpoll-max-voters" is used to specify a numeric value
      that indicates the maximum number of VOTER properties for any one
      instance of a VPOLL calendar object resource stored in a calendar
      collection.  Any attempt to store a calendar object resource with
      more VOTER properties per instance than this value MUST result in
      an error, with the CALDAV: "vpoll-max-voters" precondition
      Section 7.2 being violated.  In the absence of this property, the
      client can assume that the server can handle any number of voters
      in a VPOLL calendar component.

   Definition

   <!ELEMENT vpoll-max-voters (#PCDATA)>
   PCDATA value: a numeric value (integer greater than zero)

   <C:vpoll-max-voters xmlns:C="urn:ietf:params:xml:ns:caldav"
   >25</C:vpoll-max-voters>








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7.1.5.  CalDAV:even-more-properties

   TODO: vpoll-supported-mode poll options - e.g "vpoll-basic"

7.1.6.  Extensions to CalDAV scheduling

   This specification extends [RFC6638].

   Each section of Appendix A "Scheduling Privileges Summary" is
   extended to include VPOLL.

   Any reference to the ATTENDEE property should be read to include the
   VOTER property.  That is, for scheduling purposes the VOTER property
   is handled in exactly the same manner as the ATTENDEE property.

7.2.  Additional Preconditions for PUT, COPY, and MOVE

   This specification creates additional Preconditions for PUT, COPY,
   and MOVE methods.  These preconditions apply when a PUT operation of
   a VPOLL calendar object resource into a calendar collection occurs,
   or when a COPY or MOVE operation of a calendar object resource into a
   calendar collection occurs, or when a COPY or MOVE operation occurs
   on a calendar collection.

   The new preconditions are:

   (CALDAV:supported-vpoll-component-sets)
      The VPOLL resource submitted in the PUT request, or targeted by a
      COPY or MOVE request, MUST contain a type or combination of
      calendar component that is supported in the targeted calendar
      collection;

   (CALDAV:vpoll-max-items)
      The VPOLL resource submitted in the PUT request, or targeted by a
      COPY or MOVE request, MUST have a number of sub-components
      (excluding VTIMEZONE) less than or equal to the value of the
      "CALDAV:vpoll-max-items" property value Section 7.1.2 on the
      calendar collection where the resource will be stored;

   (CALDAV:vpoll-max-active)
      The PUT request, or COPY or MOVE request, MUST not result in the
      number of active VPOLLs being greater than the value of the
      "CALDAV:vpoll-max-active" property value Section 7.1.3 on the
      calendar collection where the resource will be stored;

   (CALDAV:vpoll-max-voters)
      The VPOLL resource submitted in the PUT request, or targeted by a
      COPY or MOVE request, MUST have a number of VOTER properties less



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      than or equal to the value of the "CALDAV:vpoll-max-voters"
      property value Section 7.1.4 on the calendar collection where the
      resource will be stored;

7.3.  CalDAV:calendar-query Report

   This allows the retrieval of VPOLLs and their included components.
   The query specification allows queries to be directed at the
   contained sub-components.  For VPOLL queries this feature is
   disallowed.  Time-range queries can only target the vpoll component
   itself.

7.3.1.  Example: Partial Retrieval of VPOLL

   In this example, the client requests the server to return specific
   components and properties of the VPOLL components that overlap the
   time range from December 4, 2012, at 00:00:00 A.M.  UTC to December
   5, 2012, at 00:00:00 A.M.  UTC.  In addition, the "DAV:getetag"
   property is also requested and returned as part of the response.
   Note that due to the CALDAV: calendar-data element restrictions, the
   DTSTAMP property in VPOLL components has not been returned, and the
   only property returned in the VCALENDAR object is VERSION.

   >> Request <<

   REPORT /cyrus/work/ HTTP/1.1
   Host: cal.example.com
   Depth: 1
   Content-Type: application/xml; charset="utf-8"
   Content-Length: xxxx

   <?xml version="1.0" encoding="utf-8" ?>
   <C:calendar-query xmlns:D="DAV:"
                 xmlns:C="urn:ietf:params:xml:ns:caldav">
     <D:prop>
       <D:getetag/>
       <C:calendar-data>
         <C:comp name="VCALENDAR">
           <C:prop name="VERSION"/>
           <C:comp name="VPOLL">
             <C:prop name="SUMMARY"/>
             <C:prop name="UID"/>
             <C:prop name="DTSTART"/>
             <C:prop name="DTEND"/>
             <C:prop name="DURATION"/>
           </C:comp>

         </C:comp>



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       </C:calendar-data>
     </D:prop>
     <C:filter>
       <C:comp-filter name="VCALENDAR">
         <C:comp-filter name="VPOLL">
           <C:time-range start="20121204T000000Z"
                         end="20121205T000000Z"/>
         </C:comp-filter>
       </C:comp-filter>
     </C:filter>
   </C:calendar-query>

   >> Response <<

   HTTP/1.1 207 Multi-Status
   Date: Sat, 11 Nov 2012 09:32:12 GMT
   Content-Type: application/xml; charset="utf-8"
   Content-Length: xxxx

   <?xml version="1.0" encoding="utf-8" ?>
   <D:multistatus xmlns:D="DAV:"
              xmlns:C="urn:ietf:params:xml:ns:caldav">
     <D:response>
       <D:href>http://cal.example.com/cyrus/work/poll2.ics</D:href>
       <D:propstat>
         <D:prop>
           <D:getetag>"fffff-abcd2"</D:getetag>
           <C:calendar-data>BEGIN:VCALENDAR
   VERSION:2.0
   BEGIN:VPOLL
   DTSTART;TZID=US/Eastern:20121202T120000
   DURATION:PT4D
   SUMMARY:Poll #2
   UID:00959BC664CA650E933C892C@example.com
   END:VPOLL
   END:VCALENDAR
   </C:calendar-data>
         </D:prop>
         <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
     </D:response>
     <D:response>
       <D:href>http://cal.example.com/cyrus/work/poll3.ics</D:href>
       <D:propstat>
         <D:prop>
           <D:getetag>"fffff-abcd3"</D:getetag>
           <C:calendar-data>BEGIN:VCALENDAR




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   VERSION:2.0
   PRODID:-//Example Corp.//CalDAV Client//EN
   BEGIN:VPOLL
   DTSTART;TZID=US/Eastern:20121204T100000
   DURATION:PT4D
   SUMMARY:Poll #3
   UID:DC6C50A017428C5216A2F1CD@example.com
   END:VPOLL
   END:VCALENDAR
   </C:calendar-data>
         </D:prop>
         <D:status>HTTP/1.1 200 OK</D:status>
       </D:propstat>
     </D:response>
   </D:multistatus>

7.4.  CalDAV time ranges

   "CALDAV:time-range XML Element" in section=9.9 [RFC4791] describes
   how to specify time ranges to limit the set of calendar components
   returned by the server.  This specification extends [RFC4791] to
   describe the meaning of time ranges for VPOLL

   A VPOLL component is said to overlap a given time range if the
   condition for the corresponding component state specified in the
   table below is satisfied.  The conditions depend on the presence of
   the DTSTART, DURATION, DTEND, COMPLETED and CREATED properties in the
   VPOLL component.  Note that, as specified above, the DTEND value MUST
   be a DATE-TIME value equal to or after the DTSTART value if
   specified.





















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   +-------------------------------------------------------------------+
   | VPOLL has the DTSTART property?                                   |
   |   +---------------------------------------------------------------+
   |   |   VPOLL has the DURATION property?                            |
   |   |   +-----------------------------------------------------------+
   |   |   | VPOLL has the DTEND property?                             |
   |   |   |   +-------------------------------------------------------+
   |   |   |   | VPOLL has the COMPLETED property?                     |
   |   |   |   |   +---------------------------------------------------+
   |   |   |   |   | VPOLL has the CREATED property?                   |
   |   |   |   |   |   +-----------------------------------------------+
   |   |   |   |   |   | Condition to evaluate                         |
   +---+---+---+---+---+-----------------------------------------------+
   | Y | Y | N | * | * | (start  <= DTSTART+DURATION)  AND             |
   |   |   |   |   |   | ((end   >  DTSTART)  OR                       |
   |   |   |   |   |   |  (end   >= DTSTART+DURATION))                 |
   +---+---+---+---+---+-----------------------------------------------+
   | Y | N | Y | * | * | ((start <  DTEND)    OR  (start <= DTSTART))  |
   |   |   |   |   |   | AND                                           |
   |   |   |   |   |   | ((end   >  DTSTART)  OR  (end   >= DTEND))    |
   +---+---+---+---+---+-----------------------------------------------+
   | Y | N | N | * | * | (start  <= DTSTART)  AND (end >  DTSTART)     |
   +---+---+---+---+---+-----------------------------------------------+
   | N | N | Y | * | * | (start  <  DTEND)    AND (end >= DTEND)       |
   +---+---+---+---+---+-----------------------------------------------+
   | N | N | N | Y | Y | ((start <= CREATED)  OR  (start <= COMPLETED))|
   |   |   |   |   |   | AND                                           |
   |   |   |   |   |   | ((end   >= CREATED)  OR  (end   >= COMPLETED))|
   +---+---+---+---+---+-----------------------------------------------+
   | N | N | N | Y | N | (start  <= COMPLETED) AND (end  >= COMPLETED) |
   +---+---+---+---+---+-----------------------------------------------+
   | N | N | N | N | Y | (end    >  CREATED)                           |
   +---+---+---+---+---+-----------------------------------------------+
   | N | N | N | N | N | TRUE                                          |
   +---+---+---+---+---+-----------------------------------------------+

8.  Security Considerations

   Applications using these property need to be aware of the risks
   entailed in using the URIs provided as values.  See [RFC3986] for a
   discussion of the security considerations relating to URIs.

9.  IANA Considerations








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9.1.  Parameter Registrations

   This document defines the following new iCalendar property parameters
   to be added to the registry defined in section=8.2.4 [RFC5545]:

             +--------------------+---------+----------------+
             | Property Parameter | Status  | Reference      |
             +--------------------+---------+----------------+
             | REQUIRED           | Current | Section 4.3.1  |
             | STAY-INFORMED      | Current | Section 4.3.2  |
             +--------------------+---------+----------------+

9.2.  Property Registrations

   This document defines the following new iCalendar properties to be
   added to the registry defined in section=8.2.3 [RFC5545]:

              +-----------------+---------+----------------+
              | Property        | Status  | Reference      |
              +-----------------+---------+----------------+
              | ACCEPT-RESPONSE | Current | Section 4.4.7  |
              | POLL-ITEM-ID    | Current | Section 4.4.3  |
              | POLL-MODE       | Current | Section 4.4.4  |
              | POLL-PROPERTIES | Current | Section 4.4.5  |
              | POLL-WINNER     | Current | Section 4.4.6  |
              | RESPONSE        | Current | Section 4.4.8  |
              | VOTER           | Current | Section 4.4.9  |
              +-----------------+---------+----------------+

9.3.  POLL-MODE Registration Template

   A poll mode is defined by completing the following template.

   Poll mode name
      The name of the poll mode.

   Purpose
      The purpose of the poll mode.  Give a short but clear description.

   Reference
      A reference to the RFC in which the poll mode is defined

9.4.  POLL-MODE Registrations

   This document defines the following registered poll modes.






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   +----------+--------------------------------------------+-----------+
   | Poll     | Purpose                                    | Reference |
   | mode     |                                            |           |
   | name     |                                            |           |
   +----------+--------------------------------------------+-----------+
   | BASIC    | To provide simple voting for a single      | Current   |
   |          | outcome from a number of candidates.       |           |
   +----------+--------------------------------------------+-----------+

10.  Acknowledgements

   The authors would like to thank the members of the Calendaring and
   Scheduling Consortium (CalConnect) for contributing their ideas and
   support.

11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2518]  Goland, Y., Whitehead, E., Faizi, A., Carter, S., and D.
              Jensen, "HTTP Extensions for Distributed Authoring --
              WEBDAV", RFC 2518, DOI 10.17487/RFC2518, February 1999,
              <https://www.rfc-editor.org/info/rfc2518>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC4791]  Daboo, C., Desruisseaux, B., and L. Dusseault,
              "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791,
              DOI 10.17487/RFC4791, March 2007,
              <https://www.rfc-editor.org/info/rfc4791>.

   [RFC5545]  Desruisseaux, B., Ed., "Internet Calendaring and
              Scheduling Core Object Specification (iCalendar)",
              RFC 5545, DOI 10.17487/RFC5545, September 2009,
              <https://www.rfc-editor.org/info/rfc5545>.

   [RFC5546]  Daboo, C., Ed., "iCalendar Transport-Independent
              Interoperability Protocol (iTIP)", RFC 5546,
              DOI 10.17487/RFC5546, December 2009,
              <https://www.rfc-editor.org/info/rfc5546>.



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   [RFC6047]  Melnikov, A., Ed., "iCalendar Message-Based
              Interoperability Protocol (iMIP)", RFC 6047,
              DOI 10.17487/RFC6047, December 2010,
              <https://www.rfc-editor.org/info/rfc6047>.

   [RFC6638]  Daboo, C. and B. Desruisseaux, "Scheduling Extensions to
              CalDAV", RFC 6638, DOI 10.17487/RFC6638, June 2012,
              <https://www.rfc-editor.org/info/rfc6638>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

11.2.  Informative References

   [IETF.TLP]
              IETF, "IETF Trust Legal Provisions (TLP)", April 2018,
              <https://trustee.ietf.org/trust-legal-provisions.html>.

   [RFC3552]  Rescorla, E. and B. Korver, "Guidelines for Writing RFC
              Text on Security Considerations", BCP 72, RFC 3552,
              DOI 10.17487/RFC3552, July 2003,
              <https://www.rfc-editor.org/info/rfc3552>.

   [RFC4918]  Dusseault, L., Ed., "HTTP Extensions for Web Distributed
              Authoring and Versioning (WebDAV)", RFC 4918,
              DOI 10.17487/RFC4918, June 2007,
              <https://www.rfc-editor.org/info/rfc4918>.

   [RFC5378]  Bradner, S., Ed. and J. Contreras, Ed., "Rights
              Contributors Provide to the IETF Trust", BCP 78, RFC 5378,
              DOI 10.17487/RFC5378, November 2008,
              <https://www.rfc-editor.org/info/rfc5378>.

Appendix A.  Open issues

   Notifications: Need to do a section on what Notifications to support.
   A.  VPOLL is about to end and you haven't voted on it yet.  Instead
   reuse VALARMS to notify the user?

   Future: Restarting a confirmed/completed VPOLL What to do with
   changes to STATUS:CONFIRMED?  Allow them or not?  What do to that
   poll had a winning event or todo.  Stress VPOLL UID MUST be unique
   Changing status back from CONFIRMED MUST adjust status of any events
   booked as a result of confirmation.  MUST winning event be cancelled
   for POLL-MODE basic?  No - VOTER has indicated now unable to attend -
   want to revote




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   Future: Voting on a confirmed/completed VPOLL Can a VOTER vote after
   completion?  May be unable to attend and wants to indicate.  Requires
   retention of VPOLL retention period Removed status

   ORGANIZER/ATTENDEE validity Can a user create a poll with scheduled
   events where that user's isn't the organizer of the poll?  So is
   there a requirement that the account that poll is on is able to
   create each one of the resources in the poll? i.e. I can't create a
   poll with a set of events where I am just the attendee of the events.
   Are there any other restrictions for components in a VPOLL?  Add to
   security consideration

   Update to existing event after poll confirm When voting on existing
   event - winning properties ONLY are merged in to the real event.

   Need to write down what isn't valid in a VPOLL a.  Can't change POLL-
   MODE

   Guide for ATTENDEE roles chair, NON-PARTICIPANT etc

   ? - some iTip notes On confirm - send itip if appropriate (PUBLISH) -
   all non-participating - shared - feeds Organizer can specify where
   result is?  Confirm can specify that itip is sent - ITIP / NONE -
   parameter ? on POLL-WINNER

   Need to add example of freebusy in response

   BEGIN:VCALENDAR
   VERSION:2.0
   PRODID:-//BedeworkCaldavTest//BedeworkCaldavTest
   METHOD: REPLY
   BEGIN:VPOLL
   ORGANIZER:mailto:douglm@mysite.edu
   VOTER:mailto:eric@example.com
   UID:sched01-1234567890
   DTSTAMP:20120101T010000Z
   SEQUENCE:0
   SUMMARY:What to do this week
   BEGIN:VFREEBUSY
   .......
   END:VFREEBUSY
   END:VPOLL
   END:VCALENDAR








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Appendix B.  Change log

   Calext V00: 2019-05-17 MD
      First calext version.  Moved source to metanorma.  No changes to
      specification.

   V03: 2014-10-28 MD

      *  Add VVOTER and VOTE components.

      *  Add RESPONSE property.

      *  Remove RESPONSE parameter from VOTER.

   V03: 2014-05-12 MD

      *  Add reply-url property and required parameter.

      *  Fix ACCEPT-RESPONSE definition.

   V02: 2014-05-12 MD

      *  Typos fixed, clarifications made.

      *  Removed spurious COMMENT param.  Switched some to PUBLIC-
         COMMENT

      *  Changed STAY-INFORMED to remove boolean value type and state
         explicit TRUE/FALSE values.

      *  iTip: Allow VPOLL DTSTART to be optional and allow
         VAVAILABILITY as subcomponent

      *  iTip: fix broken table cells

      *  Add POLL-PROPERTIES, POLL-WINNER to 5545 extensions table

      *  Added Caldav scheduling section

   V01: 2013-08-07 MD

      *  Removed method CONFIRM

      *  Removed pollitemid from VPOLL abnf.  Added text for pollwinner

      *  Added POLL-WINNER and verbiage

      *  Added STATUS values



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      *  Added RELTYPE=POLL

      *  Added supported-vpoll-component-sets

      *  Added CalDAV related parameters to VOTER

      *  Removed bad CalDAV query example.  State that queries cannot
         target the sub-components.

   Initial version: 2012-11-02 MD

Authors' Addresses

   Eric York
   California Things, Inc
   650 Main Street
   Redwood City  94063
   United States of America

   Email: eric.york@gmail.com
   URI:   www.linkedin.com/in/eryork


   Cyrus Daboo
   Apple Inc.
   1 Infinite Loop
   Cupertino  95014
   United States of America

   Email: cyrus@daboo.name
   URI:   https://www.apple.com


   Michael Douglass
   Spherical Cow Group
   226 3rd Street
   Troy  12180
   United States of America

   Email: mikeadouglass@gmail.com
   URI:   https://sphericalcowgroup.com/










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