JSON Meta Application Protocol (JMAP) for Calendars
draft-ietf-jmap-calendars-26
| Document | Type | Active Internet-Draft (jmap WG) | |
|---|---|---|---|
| Authors | Neil Jenkins , Michael Douglass | ||
| Last updated | 2025-11-04 | ||
| Replaces | draft-jenkins-jmapcalendars | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | In WG Last Call | |
| Associated WG milestone |
|
||
| Document shepherd | Joris Baum | ||
| Shepherd write-up | Show Last changed 2024-04-08 | ||
| IESG | IESG state | RFC Ed Queue | |
| Action Holders |
(None)
|
||
| Consensus boilerplate | Yes | ||
| Telechat date | (None) | ||
| Responsible AD | Orie Steele | ||
| Send notices to | joris@audriga.com | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
| IANA expert review state | Expert Reviews OK | ||
| IANA expert review comments | JMAP Capabilities, JMAP Error Codes, JMAP Data Types and JSCalendar Properties registrations have been approved. | ||
| RFC Editor | RFC Editor state | IESG | |
| Details |
draft-ietf-jmap-calendars-26
JMAP N.M. Jenkins, Ed.
Internet-Draft Fastmail
Intended status: Standards Track M. Douglass, Ed.
Expires: 9 May 2026 Spherical Cow Group
5 November 2025
JSON Meta Application Protocol (JMAP) for Calendars
draft-ietf-jmap-calendars-26
Abstract
This document specifies a data model for synchronizing calendar data
with a server using JMAP. Clients can use this to efficiently read,
write, and share calendars and events, receive push notifications for
changes or event reminders, and keep track of changes made by others
in a multi-user environment.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 9 May 2026.
Copyright Notice
Copyright (c) 2025 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
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 4
1.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.4. Data Model Overview . . . . . . . . . . . . . . . . . . . 5
1.4.1. UIDs and CalendarEvent Ids . . . . . . . . . . . . . 6
1.5. Addition to the Capabilities Object . . . . . . . . . . . 6
1.5.1. urn:ietf:params:jmap:calendars . . . . . . . . . . . 6
1.5.2. urn:ietf:params:jmap:principals:availability . . . . 7
1.5.3. urn:ietf:params:jmap:calendars:parse . . . . . . . . 8
2. Principals and Sharing . . . . . . . . . . . . . . . . . . . 8
2.1. Principal Capability urn:ietf:params:jmap:calendars . . . 8
2.2. Principal/getAvailability . . . . . . . . . . . . . . . . 8
2.3. Principal/query extension . . . . . . . . . . . . . . . . 11
3. Participant Identities . . . . . . . . . . . . . . . . . . . 11
3.1. ParticipantIdentity/get . . . . . . . . . . . . . . . . . 12
3.2. ParticipantIdentity/changes . . . . . . . . . . . . . . . 12
3.3. ParticipantIdentity/set . . . . . . . . . . . . . . . . . 12
4. Calendars . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1. Calendar/get . . . . . . . . . . . . . . . . . . . . . . 18
4.2. Calendar/changes . . . . . . . . . . . . . . . . . . . . 18
4.3. Calendar/set . . . . . . . . . . . . . . . . . . . . . . 18
5. Calendar Events . . . . . . . . . . . . . . . . . . . . . . . 20
5.1. Additional common-use JSCalendar properties . . . . . . . 22
5.1.1. mayInviteSelf . . . . . . . . . . . . . . . . . . . . 22
5.1.2. mayInviteOthers . . . . . . . . . . . . . . . . . . . 22
5.1.3. hideAttendees . . . . . . . . . . . . . . . . . . . . 23
5.2. Additional reserved JSCalendar properties . . . . . . . . 23
5.2.1. scheduleSequence . . . . . . . . . . . . . . . . . . 23
5.2.2. scheduleUpdated . . . . . . . . . . . . . . . . . . . 23
5.3. Attachments . . . . . . . . . . . . . . . . . . . . . . . 24
5.4. Per-user properties . . . . . . . . . . . . . . . . . . . 24
5.5. Recurring events . . . . . . . . . . . . . . . . . . . . 24
5.6. Updating for "this-and-future" . . . . . . . . . . . . . 25
5.6.1. Splitting an event . . . . . . . . . . . . . . . . . 25
5.6.2. Updating the base event and overriding previous . . . 25
5.7. CalendarEvent/get . . . . . . . . . . . . . . . . . . . . 26
5.8. CalendarEvent/changes . . . . . . . . . . . . . . . . . . 27
5.9. CalendarEvent/set . . . . . . . . . . . . . . . . . . . . 28
5.9.1. Patching . . . . . . . . . . . . . . . . . . . . . . 31
5.9.2. Sending invitations and responses . . . . . . . . . . 34
5.10. CalendarEvent/copy . . . . . . . . . . . . . . . . . . . 36
5.11. CalendarEvent/query . . . . . . . . . . . . . . . . . . . 36
5.11.1. Filtering . . . . . . . . . . . . . . . . . . . . . 37
5.11.2. Sorting . . . . . . . . . . . . . . . . . . . . . . 39
5.12. CalendarEvent/queryChanges . . . . . . . . . . . . . . . 39
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5.13. CalendarEvent/parse . . . . . . . . . . . . . . . . . . . 40
6. Alerts . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.1. Default alerts . . . . . . . . . . . . . . . . . . . . . 41
6.2. Acknowledging an alert . . . . . . . . . . . . . . . . . 42
6.3. Snoozing an alert . . . . . . . . . . . . . . . . . . . . 42
6.4. Push events . . . . . . . . . . . . . . . . . . . . . . . 42
7. Calendar Event Notifications . . . . . . . . . . . . . . . . 43
7.1. CalendarEventNotification/get . . . . . . . . . . . . . . 45
7.2. CalendarEventNotification/changes . . . . . . . . . . . . 45
7.3. CalendarEventNotification/set . . . . . . . . . . . . . . 45
7.4. CalendarEventNotification/query . . . . . . . . . . . . . 45
7.4.1. Filtering . . . . . . . . . . . . . . . . . . . . . . 45
7.4.2. Sorting . . . . . . . . . . . . . . . . . . . . . . . 46
7.5. CalendarEventNotification/queryChanges . . . . . . . . . 46
8. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 46
8.1. Fetching initial data . . . . . . . . . . . . . . . . . . 46
8.2. Creating an event . . . . . . . . . . . . . . . . . . . . 49
8.3. Snoozing an alert . . . . . . . . . . . . . . . . . . . . 51
8.4. Changing the default calendar . . . . . . . . . . . . . . 54
8.5. Parsing an iCalendar file . . . . . . . . . . . . . . . . 54
9. Security Considerations . . . . . . . . . . . . . . . . . . . 56
9.1. Privacy . . . . . . . . . . . . . . . . . . . . . . . . . 56
9.2. Spoofing . . . . . . . . . . . . . . . . . . . . . . . . 56
9.3. Denial-of-service . . . . . . . . . . . . . . . . . . . . 57
9.3.1. Expanding Recurrences . . . . . . . . . . . . . . . . 57
9.3.2. Firing alerts . . . . . . . . . . . . . . . . . . . . 57
9.3.3. Load spikes . . . . . . . . . . . . . . . . . . . . . 57
9.4. Spam . . . . . . . . . . . . . . . . . . . . . . . . . . 58
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58
10.1. JMAP Capability Registration for "calendars" . . . . . . 58
10.2. JMAP Capability Registration for
"principals:availability" . . . . . . . . . . . . . . . 58
10.3. JMAP Data Type Registration for "Calendar" . . . . . . . 58
10.4. JMAP Data Type Registration for "CalendarEvent" . . . . 59
10.5. JMAP Data Type Registration for
"CalendarEventNotification" . . . . . . . . . . . . . . 59
10.6. JMAP Data Type Registration for "ParticipantIdentity" . 59
10.7. JMAP Error Codes Registry . . . . . . . . . . . . . . . 59
10.7.1. calendarHasEvent . . . . . . . . . . . . . . . . . . 59
10.7.2. noSupportedScheduleMethods . . . . . . . . . . . . . 60
10.7.3. expandDurationTooLarge . . . . . . . . . . . . . . . 60
10.7.4. cannotCalculateOccurrences . . . . . . . . . . . . . 60
10.8. Update to the JSCalendar Properties Registry . . . . . . 60
10.8.1. Update to "JSCalendar Properties" Registry
Template . . . . . . . . . . . . . . . . . . . . . . 60
10.8.2. Initial values for existing registrations . . . . . 61
10.9. JSCalendar Property Registrations . . . . . . . . . . . 61
10.9.1. id . . . . . . . . . . . . . . . . . . . . . . . . . 61
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10.9.2. baseEventId . . . . . . . . . . . . . . . . . . . . 61
10.9.3. calendarIds . . . . . . . . . . . . . . . . . . . . 61
10.9.4. isDraft . . . . . . . . . . . . . . . . . . . . . . 61
10.9.5. isOrigin . . . . . . . . . . . . . . . . . . . . . . 62
10.9.6. utcStart . . . . . . . . . . . . . . . . . . . . . . 62
10.9.7. utcEnd . . . . . . . . . . . . . . . . . . . . . . . 62
10.9.8. useDefaultAlerts . . . . . . . . . . . . . . . . . . 62
10.9.9. mayInviteSelf . . . . . . . . . . . . . . . . . . . 62
10.9.10. mayInviteOthers . . . . . . . . . . . . . . . . . . 62
10.9.11. hideAttendees . . . . . . . . . . . . . . . . . . . 63
10.9.12. scheduleSequence . . . . . . . . . . . . . . . . . . 63
10.9.13. scheduleUpdated . . . . . . . . . . . . . . . . . . 63
10.9.14. blobId . . . . . . . . . . . . . . . . . . . . . . . 63
11. Normative References . . . . . . . . . . . . . . . . . . . . 63
12. Informative References . . . . . . . . . . . . . . . . . . . 65
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 65
1. Introduction
JMAP ([RFC8620] — JSON Meta Application Protocol) is a generic
protocol for synchronizing data, such as mail, calendars or contacts,
between a client and a server. It is optimized for mobile and web
environments, and aims to provide a consistent interface to different
data types.
This specification defines a data model for synchronizing calendar
data between a client and a server using JMAP. The data model is
designed to allow a server to provide consistent access to the same
data via CalDAV [RFC4791] as well as JMAP, however the functionality
offered over the two protocols may differ. Unlike CalDAV, this
specification does not define access to tasks or journal entries
(VTODO or VJOURNAL iCalendar components in CalDAV).
1.1. Notational Conventions
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 BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Type signatures, examples, and property descriptions in this document
follow the conventions established in Section 1.1 of [RFC8620].
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1.2. Data Types
The Id data type defined in Section 1.2 of [RFC8620] is used in this
document. So too are the UnsignedInt, UTCDateTime, LocalDateTime,
Duration, and TimeZoneId data types defined in Sections 1.4.3, 1.4.4,
1.4.5, 1.4.6, and 1.4.8 of [I-D.ietf-calext-jscalendarbis]
respectively.
1.3. Terminology
The same terminology is used in this document as in the core JMAP
specification, see Section 1.6 of [RFC8620].
The terms ParticipantIdentity, Calendar, CalendarEvent, and
CalendarEventNotification (with these specific capitalizations) are
used to refer to the data types defined in this document and
instances of those data types.
1.4. Data Model Overview
An Account (see Section 1.6.2 of [RFC8620]) with support for the
calendar data model contains zero or more Calendar objects, which is
a named collection of CalendarEvents. Calendars can also provide
defaults, such as alerts and a color to apply to events in the
calendar. Clients commonly let users toggle visibility of events
belonging to a particular calendar on/off. Servers may allow an
event to belong to multiple Calendars within an account.
A CalendarEvent is a representation of an event or recurring series
of events in JSCalendar Event [I-D.ietf-calext-jscalendarbis] format.
Simple clients may ask the server to expand recurrences for them
within a specific time period, and optionally convert times into UTC
so they do not have to handle time zone conversion. More full-
featured clients will want to access the full event information and
handle recurrence expansion and time zone conversion locally.
CalendarEventNotification objects keep track of the history of
changes made to a calendar by other users, allowing calendar clients
to notify the user of changes to their schedule.
The ParticipantIdentity data type represents the identities of the
current user within an Account, which determines which events the
user is a participant of and possibly their permissions related to
that event.
In servers with support for JMAP Sharing [RFC9670], data may be
shared with other users. Sharing permissions are managed per
calendar. For example, an individual may have separate calendars for
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personal and work activities, with both contributing to their free-
busy availability, but only the work calendar shared in its entirety
with colleagues. Principals (see Section 2 of [RFC9670]) may also
represent schedulable entities, such as a meeting room.
Users can normally subscribe to any calendar to which they have
access. This indicates the user wants this calendar to appear in
their regular list of calendars. The separate "isVisible" property
stores whether the user would currently like to view the events in a
subscribed calendar.
1.4.1. UIDs and CalendarEvent Ids
Each CalendarEvent has a "uid" property (Section 4.1.1 of
[I-D.ietf-calext-jscalendarbis]), which is a globally unique
identifier that identifies the same event in different Accounts, or
different instances of the same recurring event within an Account.
An Account MUST NOT contain more than one CalendarEvent with the same
uid unless all of the CalendarEvent objects have distinct, non-null
values for their "recurrenceId" property. (This situation occurs if
the Principal is added to one or more specific instances of a
recurring event without being invited to the whole series.)
Each CalendarEvent also has an id, which is scoped to the JMAP
Account and used for referencing it in JMAP methods. There is no
necessary link between the uid and the CalendarEvent's id.
CalendarEvents with the same uid in different Accounts may have
different ids.
1.5. Addition to the Capabilities Object
The capabilities object is returned as part of the JMAP Session
object; see Section 2 of [RFC8620]. This document defines three
additional capability URIs.
1.5.1. urn:ietf:params:jmap:calendars
This represents support for the Calendar, CalendarEvent,
CalendarEventNotification, and ParticipantIdentity data types and
associated API methods, except for "CalendarEvent/parse". The value
of this property in the JMAP Session "capabilities" property is an
empty object.
The value of this property in an account's "accountCapabilities"
property is an object that MUST contain the following information on
server capabilities and permissions for that account:
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*maxCalendarsPerEvent*: UnsignedInt|null
The maximum number of Calendars (see Section 4) that can be
assigned to a single CalendarEvent object (see Section 5). This
MUST be an integer >= 1, or null for no limit (or rather, the
limit is always the number of Calendars in the account).
*minDateTime*: UTCDateTime
The earliest date-time value the server is willing to accept for
any date stored in a CalendarEvent.
*maxDateTime*: UTCDateTime
The latest date-time value the server is willing to accept for any
date stored in a CalendarEvent.
*maxExpandedQueryDuration*: Duration
The maximum duration the user may query over when asking the
server to expand recurrences.
*maxParticipantsPerEvent*: UnsignedInt|null
The maximum number of participants a single event may have, or
null for no limit.
*mayCreateCalendar*: Boolean
If true, the user may create a calendar in this account.
1.5.2. urn:ietf:params:jmap:principals:availability
Represents support for the "Principal/getAvailability" method. Any
account with this capability MUST also have the
urn:ietf:params:jmap:principals capability (see Section 1.5.1 of
[RFC9670]).
The value of this property in the JMAP Session "capabilities"
property is an empty object.
The value of this property in an account's "accountCapabilities"
property is an object that MUST contain the following information on
server capabilities and permissions for that account:
*maxAvailabilityDuration*: Duration
The maximum duration over which the server is prepared to
calculate availability in a single call (see Section 2.2).
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1.5.3. urn:ietf:params:jmap:calendars:parse
This represents support for the CalendarEvent/parse method (see
Section 5.13). The value of this property is an empty object in both
the JMAP session "capabilities" property and an account's
"accountCapabilities" property.
2. Principals and Sharing
For systems that also support JMAP Sharing [RFC9670], the
urn:ietf:params:jmap:calendars capability is used to indicate that
this Principal may be used with calendaring. A new method is defined
to allow users to query availability when scheduling events.
2.1. Principal Capability urn:ietf:params:jmap:calendars
A "urn:ietf:params:jmap:calendars" property is added to the Principal
"capabilities" object, the value of which is an object with the
following properties:
*accountId*: Id|null
Id of Account with the urn:ietf:params:jmap:calendars capability
that contains the calendar data for this Principal, or null if
either (a) there is none (e.g. the Principal is a group just used
for permissions management), or (b) the user does not have access
to any data in the account (with the exception of free/busy, which
is governed by the "mayGetAvailability" property). The
corresponding Account object can be found in the Principal's
"accounts" property, as per Section 2 of [RFC9670].
*mayGetAvailability*: Boolean
If true, the user may call the "Principal/getAvailability" method
with this Principal.
*mayShareWith*: Boolean
If true, the user may add this Principal as a calendar share
target (by adding them to the "shareWith" property of a calendar,
see Section 4).
*calendarAddress*: String
If this Principal may be added as a participant to an event, this
is the calendarAddress to use to receive iTIP scheduling messages.
2.2. Principal/getAvailability
This method calculates the availability of the Principal for
scheduling within a requested time period. It takes the following
arguments:
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*accountId*: Id
The id of the account to use.
*id*: Id
The id of the Principal to calculate availability for.
*utcStart*: UTCDateTime
The start time (inclusive) of the period for which to return
availability.
*utcEnd*: UTCDateTime
The end time (exclusive) of the period for which to return
availability.
*showDetails*: Boolean
If true, event details will be returned if the user has permission
to view them.
*eventProperties*: String[]|null
A list of properties to include in any CalendarEvent object
returned. If null, all properties of the event will be returned.
Otherwise, only properties with names in the given list will be
returned.
The server will first find all relevant events, expanding any
recurring events. Relevant events are ones where all of the
following is true:
* The Principal is subscribed to the calendar.
* The "includeInAvailability" property of the calendar for the
Principal is "all" or "attending".
* The user has the "mayReadFreeBusy" permission for the calendar.
* The event finishes after the "utcStart" argument and starts before
the "utcEnd" argument.
* The event's "privacy" property is not "secret".
* The "freeBusyStatus" property of the event is "busy" (or omitted,
as this is the default).
* The "status" property of the event is not "cancelled".
* If the "includeInAvailability" property of the calendar is
"attending", then the Principal is a participant of the event, and
has a "participationStatus" of "accepted" or "tentative".
If an event is in more than one calendar, it is relevant if all of
the above are true for any one calendar that it is in.
The server then generates a BusyPeriod object for each of these
events. A *BusyPeriod* object has the following properties:
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*utcStart*: UTCDateTime
The start time (inclusive) of the period this represents.
*utcEnd*: UTCDateTime
The end time (exclusive) of the period this represents.
*busyStatus*: String (optional, default "unavailable")
This MUST be one of:
* "confirmed" — The event status is "confirmed" and the
Principal's "participationStatus" is "attending".
* "tentative" — The event status is "tentative" or the
Principal's "participationStatus" is "tentative".
* "unavailable" — The Principal is not available for scheduling
at this time for any other reason.
*event*: CalendarEvent|null
The CalendarEvent representation of the event (see Section 5), or
null if any of the following are true:
* The "showDetails" argument is false.
* The "privacy" property of the event is "private".
* The user does not have the "mayReadItems" permission for any of
the calendars the event is in.
If an "eventProperties" argument was given, any properties in the
JSCalendar Event that are not in the eventProperties list are
removed from the returned representation.
*accountId*: Id|null
The account id in which this event can be found, or null if the
"event" property is null. (The id of the event may be requested
in the eventProperties.)
The server MAY also generate BusyPeriod objects based on other
information it has about the Principal's availability, such as office
hours; the "event" and "accountId" properties will always be null for
these.
Finally, the server MUST merge and split BusyPeriod objects where the
"event" property is null, such that none of them overlap and either
there is a gap in time between any two objects (the utcEnd of one
does not equal the utcStart of another) or those objects have a
different "busyStatus" property. If there are overlapping BusyPeriod
time ranges with different "busyStatus" properties the server MUST
choose the value in the following order: confirmed > unavailable >
tentative.
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The response has the following argument:
*list*: BusyPeriod[]
The list of BusyPeriod objects calculated as described above.
The following additional errors may be returned instead of the
"Principal/getAvailability" response:
*notFound*
No Principal with this id exists, or the user does not have
permission to see that this Principal exists.
*forbidden*
The user does not have permission to query this Principal's
availability.
*tooLarge*
The duration between utcStart and utcEnd is longer than the server
is willing to calculate availability for.
*rateLimit*
Too many availability requests have been made recently and the
user is being rate limited. It may work to try again later.
2.3. Principal/query extension
The following extra optional property is added to the
*FilterCondition* object for the *Principal/query* method when the
urn:ietf:params:jmap:principals:availability capability is used:
*calendarAddress*: String
The given string is a calendarAddress belonging to the Principal.
3. Participant Identities
A ParticipantIdentity stores information about a URI that represents
the user within that account in an event's participants.
A *ParticipantIdentity* object has the following properties:
*id*: Id (immutable; server-set)
The id of the ParticipantIdentity.
*name*: String (default: "")
The display name of the participant to use when adding this
participant to an event, e.g. "Joe Bloggs".
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*calendarAddress*: String
The URI that represents this participant for iTIP scheduling
[RFC5546].
*isDefault*: Boolean (server-set)
This SHOULD be true for exactly one participant identity in any
account, and MUST NOT be true for more than one participant
identity within an account. The default identity should be used
by clients whenever they need to choose an identity for the user
within this account, and they do not have any other information on
which to make a choice. For example, if creating a scheduled
event in this account, the default identity may be automatically
added as an owner. (But the client may ignore this if, for
example, it has its own feature to allow users to choose which
identity to use based on the invitees.)
If no participant identities have "isDefault" set, users with
multiple clients may experience different default choices in each
client, which can be confusing or lead to the wrong identity being
used by accident.
A participant in an event corresponds to a ParticipantIdentity if the
"calendarAddress" property of the participant is equivalent to the
"calendarAddress" property of the identity after syntax-based
normalisation, as per Section 6.2.2 of [RFC3986].
The following JMAP methods are supported.
3.1. ParticipantIdentity/get
This is a standard "/get" method as described in Section 5.1 of
[RFC8620]. The "ids" argument may be null to fetch all at once.
3.2. ParticipantIdentity/changes
This is a standard "/changes" method as described in Section 5.2 of
[RFC8620].
3.3. ParticipantIdentity/set
This is a standard "/set" method as described in Section 5.3 of
[RFC8620], but with the following additional request argument:
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*onSuccessSetIsDefault*: Id|null
If an id is given, and all creates, updates and destroys (if any)
succeed without error, the server will try to set this identity as
the default. (For references to ParticipantIdentity creations,
this is equivalent to a creation-reference, so the id will be the
creation id prefixed with a "#".)
If the id is not found, or the change is not permitted by the server
for policy reasons, it MUST be ignored and the currently default
ParticipantIdentity (if any) will remain as such. No error is
returned to the client in this case.
As per Section 5.3 of [RFC8620], if the default is successfully
changed, any changed objects MUST be reported in either the "created"
or "updated" argument in the response as appropriate, with the
server-set value included.
The server MAY restrict the URI values the user may claim, for
example only allowing mailto: URIs with email addresses that belong
to the user. A standard forbidden error is returned to reject non-
permissible changes.
4. Calendars
A Calendar is a named collection of events. All events are
associated with at least one calendar.
A *Calendar* object has the following properties:
*id*: Id (immutable; server-set)
The id of the calendar.
*name*: String
The user-visible name of the calendar. This MUST NOT be the empty
string and MUST NOT be greater than 255 octets in size when
encoded as UTF-8.
*description*: String|null (default: null)
An optional longer-form description of the calendar, to provide
context in shared environments where users need more than just the
name.
*color*: String|null (default: null)
A color to be used when displaying events associated with the
calendar.
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If not null, the value MUST be a case-insensitive color name taken
from the set of names defined in Section 4.3 of CSS Color Module
Level 3 [COLORS], or an RGB value in hexadecimal notation, as
defined in Section 4.2.1 of CSS Color Module Level 3.
The color SHOULD have sufficient contrast when used as text on a
white background, unless the user explicitly chooses otherwise.
The Web Content Accessibility Guidelines [WCAG] recommend at least
a 4.5:1 contrast ratio for readability.
*sortOrder*: UnsignedInt (default: 0)
Defines the sort order of calendars when presented in the client's
UI, so it is consistent between devices. The number MUST be an
integer in the range 0 <= sortOrder < 2^(31.)
A calendar with a lower order is to be displayed before a calendar
with a higher order in any list of calendars in the client's UI.
Calendars with equal order should be sorted in alphabetical order
by name. The sorting should take into account locale-specific
character order convention.
*isSubscribed*: Boolean
True if the user has indicated they wish to see this Calendar in
their client. This SHOULD default to false for Calendars in
shared accounts the user has access to and true for any new
Calendars created by the user themself.
If false, the calendar SHOULD only be displayed when the user
explicitly requests it or to offer it for the user to subscribe
to. For example, a company may have a large number of shared
calendars which all employees have permission to access, but the
user would only subscribe to the ones they care about and want to
be able to have normally accessible.
*isVisible*: Boolean (default: true)
If true, the calendar's events should be displayed to the user.
If false, the user has indicated they wish to temporarily hide
this calendar's events. Clients MUST ignore this property if
isSubscribed is false. If an event is in multiple calendars, it
should be displayed if isVisible is true for any of those
calendars.
*isDefault*: Boolean (server-set)
This SHOULD be true for exactly one calendar in any account, and
MUST NOT be true for more than one calendar within an account.
The default calendar should be used by clients whenever they need
to choose a calendar for the user within this account, and they do
not have any other information on which to make a choice. For
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example, if the user creates a new event, the client may
automatically set the event as belonging to the default calendar
from the user's primary account.
*includeInAvailability*: String
This determines which events in this calendar will be used as part
of availability calculation. The value MUST be one of:
* "all" — all events are considered.
* "attending" — events the user is a confirmed or tentative
participant of are considered.
* "none" — all events are ignored (but may be considered if also
in another calendar).
This should default to "all" for the calendars in the user's own
account, and "none" for calendars shared with the user.
*defaultAlertsWithTime*: Id[Alert]|null
A map of alert ids to Alert objects (see Section 4.5.1 of
[I-D.ietf-calext-jscalendarbis]) to apply for events where
"showWithoutTime" is false and "useDefaultAlerts" is true. Ids
MUST be unique across all default alerts in the account, including
those in other calendars; a UUID [RFC9562] is recommended. The
"trigger" MUST NOT be an AbsoluteTrigger, as this would fire for
every event at the same time and so does not make sense for a
default alert.
If omitted on creation, the default is server dependent. For
example, servers may choose to always default to null, or may copy
the alerts from the default calendar.
*defaultAlertsWithoutTime*: Id[Alert]|null
A map of alert ids to Alert objects (see Section 4.5.1 of
[I-D.ietf-calext-jscalendarbis]) to apply for events where
"showWithoutTime" is true (commonly referred to as "all day"
events) and "useDefaultAlerts" is true. Ids MUST be unique across
all default alerts in the account, including those in other
calendars; a UUID [RFC9562] is recommended. The "trigger" MUST
NOT be an AbsoluteTrigger, as this would fire for every event at
the same time and so does not make sense for a default alert.
If omitted on creation, the default is server dependent. For
example, servers may choose to always default to null, or may copy
the alerts from the default calendar.
*timeZone*: TimeZoneId|null (default: null)
The time zone to use for events without a time zone when the
server needs to resolve them into absolute time, e.g., for alerts
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or availability calculation. The value MUST be a time zone id
from the IANA Time Zone Database [IANA-TZDB]. If null, the
timeZone of the account's associated Principal will be used.
*shareWith*: Id[CalendarRights]|null (default: null)
This is a map configuring who the calendar is shared with, or null
if it is not shared with anyone. Each key in the map is the id of
a Principal with whom the calendar is shared. The value for each
key is the set of access rights that Principal has for the
calendar. The account id for the Principals may be found in the
urn:ietf:params:jmap:principals:owner capability of the Account to
which the calendar belongs.
The Principal to which this calendar belongs MUST NOT be in the
map.
The property may only be modified if the user has the mayShare
right.
*myRights*: CalendarRights (server-set)
The set of access rights the user has in relation to this
Calendar. If any event is in multiple calendars, the user has the
following rights:
* The user may fetch the event if they have the mayReadItems
right on any calendar the event is in.
* The user may remove an event from a calendar (by modifying the
event's "calendarIds" property) if the user has the appropriate
permission for that calendar.
* The user may make other changes to the event if they have the
right to do so in *all* calendars to which the event belongs.
A *CalendarRights* object has the following properties:
*mayReadFreeBusy*: Boolean
The user may read the free-busy information for this calendar as
part of a call to "Principal/getAvailability" (see Section 2.2).
*mayReadItems*: Boolean
The user may fetch the events in this calendar.
*mayWriteAll*: Boolean
The user may create, modify or destroy all events in this
calendar, or move events to or from this calendar. If this is
true, the mayWriteOwn, mayUpdatePrivate and mayRSVP properties
MUST all also be true.
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*mayWriteOwn*: Boolean
The user may create, modify or destroy an event on this calendar
if either they are the owner of the event (see below) or the event
has no owner. This means the user may also transfer ownership by
updating an event so they are no longer an owner.
*mayUpdatePrivate*: Boolean
The user may modify per-user properties (see Section 5.4) on all
events in the calendar, even if they would not otherwise have
permission to modify that event. These properties MUST all be
stored per-user, and changes do not affect any other user of the
calendar.
The user may also modify these properties on a per-occurrence
basis for recurring events (updating the "recurrenceOverrides"
property of the event to do so).
*mayRSVP*: Boolean
The user may modify the following properties of any Participant
object that corresponds to one of the user's ParticipantIdentity
objects in the account, even if they would not otherwise have
permission to modify that event:
* participationStatus
* expectReply
* scheduleSequence
* scheduleUpdated
If the event has its "mayInviteSelf" property set to true (see
Section 5.1.1), then the user may also add a new Participant to
the event with a calendarAddress property that is the same as the
calendarAddress property of one of the user's ParticipantIdentity
objects in the account. The "roles" property of the participant
MUST only contain "attendee".
If the event has its "mayInviteOthers" property set to true (see
Section 5.1.2) and there is an existing Participant in the event
corresponding to one of the user's ParticipantIdentity objects in
the account, then the user may also add new participants. The
"roles" property of any new participant MUST only contain
"attendee".
The user may also do all of the above on a per-occurrence basis
for recurring events (updating the "recurrenceOverrides" property
of the event to do so).
*mayShare*: Boolean
The user may modify the "shareWith" property for this calendar.
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*mayDelete*: Boolean
The user may delete the calendar itself.
The user is an *owner* for an event if the CalendarEvent object has a
"participants" property, and one of the Participant objects both:
a. Has the "owner" role.
b. Corresponds to one of the user's ParticipantIdentity objects in
the account (as per Section 3).
An event has no owner if its "participants" property is null or
omitted, or if none of the Participant objects have the "owner" role.
4.1. Calendar/get
This is a standard "/get" method as described in Section 5.1 of
[RFC8620]. The "ids" argument may be null to fetch all at once.
If mayReadFreeBusy is the only permission the user has, the calendar
MUST NOT be returned in "Calendar/get" and "Calendar/query"; it must
behave as though it did not exist. The data is just used as part of
"Principal/getAvailability".
4.2. Calendar/changes
This is a standard "/changes" method as described in Section 5.2 of
[RFC8620].
4.3. Calendar/set
This is a standard "/set" method as described in Section 5.3 of
[RFC8620] but with the following additional request arguments:
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*onDestroyRemoveEvents*: Boolean (default: false)
If false, any attempt to destroy a Calendar that still has
CalendarEvents in it will be rejected with a calendarHasEvent
SetError. If true, any CalendarEvents that were in the Calendar
will be removed from it, and if in no other Calendars they will be
destroyed. This MUST NOT send scheduling messages to
participants. It MAY create CalendarEventNotification objects, if
deemed likely to be helpful to the user. In the case of a
calendar with a large number of events, the large number of
notifications resulting from the single deletion is unlikely to be
useful to the user, and the server MAY choose to omit creating
them. In systems supporting JMAP Sharing, a single
ShareNotification (as defined in Section 3 of [RFC9670]) MUST be
created for each Principal the calendar was previously shared
with, to inform them they no longer have access to the calendar.
*onSuccessSetIsDefault*: Id|null
If an id is given, and all creates, updates and destroys (if any)
succeed without error, the server will try to set this calendar as
the default. (For references to Calendar creations, this is
equivalent to a creation-reference, so the id will be the creation
id prefixed with a "#".)
If the id is not found, or the change is not permitted by the
server for policy reasons, it MUST be ignored and the currently
default calendar (if any) will remain as such. No error is
returned to the client in this case.
As per Section 5.3 of [RFC8620], if the default is successfully
changed, any changed objects MUST be reported in either the
"created" or "updated" argument in the response as appropriate,
with the server-set value included.
The "shareWith" property may only be set by users that have the
mayShare right. When modifying the "shareWith" property, the user
cannot give a right to a Principal if the Principal did not already
have that right and the user making the change also does not have
that right. Any attempt to do so must be rejected with a forbidden
SetError.
Users can subscribe or unsubscribe to a calendar by setting the
"isSubscribed" property. The server MAY forbid users from
subscribing to certain calendars even though they have permission to
see them, rejecting the update with a forbidden SetError.
The following properties may be set by anyone who is subscribed to
the calendar and are always stored per-user:
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* name
* color
* sortOrder
* isVisible
* timeZone
* includeInAvailability
* defaultAlertsWithoutTime
* defaultAlertsWithTime
The "name", "color", and "timeZone" properties are initially
inherited from the owner's copy of the calendar, but if set by a user
with whom the calendar is shared, they then get their own copy of the
property. This does not change the value for any other users. If
the value of the property in the owner's calendar changes after this,
it does not overwrite any user's custom value.
The "sortOrder", "isVisible", "includeInAvailability",
"defaultAlertsWithTime", and "defaultAlertsWithoutTime" properties
are initially the default value for each user with whom the calendar
is shared; they are not inherited from the owner.
The following extra SetError type is defined:
For "destroy":
*calendarHasEvent*
The Calendar has at least one CalendarEvent assigned to it, and
the "onDestroyRemoveEvents" argument was false.
5. Calendar Events
A *CalendarEvent* object contains information about an event, or
recurring series of events, that takes place at a particular time.
It is a JSCalendar Event object, as defined in
[I-D.ietf-calext-jscalendarbis], with the following additional
properties:
*id*: Id (immutable; server-set)
The id of the CalendarEvent. The id uniquely identifies a
JSCalendar Event with a particular uid and recurrenceId within a
particular account.
*baseEventId*: Id|null (immutable; server-set)
This is only defined if the "id" property is a synthetic id,
generated by the server to represent a particular instance of a
recurring event (see Section 5.11). This property gives the id of
the "real" CalendarEvent this was generated from.
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*calendarIds*: Id[Boolean]
The set of Calendar ids this event belongs to. An event MUST
belong to one or more Calendars at all times (until it is
destroyed). The set is represented as an object, with each key
being a Calendar id. The value for each key in the object MUST be
true.
*isDraft*: Boolean (default: false)
If true, this event is to be considered a draft. The server will
not send any scheduling messages to participants or send push
notifications for alerts. This may only be set to true upon
creation. Once set to false, the value cannot be updated to true.
This property MUST NOT appear in "recurrenceOverrides".
*isOrigin*: Boolean (server-set)
Is this the authoritative source for this event (i.e., does it
control scheduling for this event; the event has not been added as
a result of an invitation from another calendar system)? This is
true if, and only if:
* the event's "organizerCalendarAddress" property is null; or
* the account will receive messages sent to the
"organizerCalendarAddress" URI.
*utcStart*: UTCDateTime
For simple clients that do not implement time zone support.
Clients should only use this if also asking the server to expand
recurrences, as you cannot accurately expand a recurrence without
the original time zone.
This property is calculated at fetch time by the server. Time
zones are political and they can and do change at any time.
Fetching exactly the same property again may return a different
result if the time zone data has been updated on the server. Time
zone data changes are not considered "updates" to the event.
If set, the server will convert the UTC date to the event's
current time zone and store the local time. If the event does not
have a non-null "timeZone" property, the server MUST also set this
property (and return it in the created/updated response, as per
Section 5.3 of [RFC8620]). The value MUST be the "timeZone"
property of the Calendar(s) the event is in if all of them have
the same non-null value. Otherwise, the time zone is to be set to
"Etc/UTC".
This property is not included in "CalendarEvent/get" responses by
default and must be requested explicitly.
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Floating events (events without a time zone) will be interpreted
as per the time zone given as a "CalendarEvent/get" argument.
Note that it is not possible to accurately calculate the expansion
of a recurrence rule or recurrence overrides with the "utcStart"
property rather than the local start time. Even simple
recurrences such as "repeat weekly" may cross a daylight-savings
boundary and end up at a different UTC time. Clients that wish to
use "utcStart" are RECOMMENDED to request the server expand
recurrences (see Section 5.11).
*utcEnd*: UTCDateTime
The server calculates the end time in UTC from the start/timeZone/
duration properties of the event. This property is not included
by default and must be requested explicitly. Like utcStart, it is
calculated at fetch time if requested and may change due to time
zone data changes. Floating events will be interpreted as per the
time zone given as a "CalendarEvent/get" argument.
*useDefaultAlerts*: Boolean (optional, default: false)
If true, use the user's default alerts and ignore the value of the
alerts property (see Section 6.1).
CalendarEvent objects MUST NOT have a "method" property as this is
only used when representing iTIP [RFC5546] scheduling messages, not
events in a data store.
5.1. Additional common-use JSCalendar properties
This document defines three new JSCalendar properties for common use.
5.1.1. mayInviteSelf
Type: Boolean (default: false)
Context: Event, Task
If true, anyone may add themselves to the event as a participant with
the "attendee" role. This property MUST NOT be altered in the
recurrenceOverrides; it may only be set on the base object.
5.1.2. mayInviteOthers
Type: Boolean (default: false)
Context: Event, Task
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If true, any current participant with the "attendee" role may add new
participants with the "attendee" role to the event. This property
MUST NOT be altered in the recurrenceOverrides; it may only be set on
the base object.
5.1.3. hideAttendees
Type: Boolean (default: false)
Context: Event, Task
If true, only the owners of the event may see the full set of
participants. Other users with access to the event may only see the
owners and themselves. This property MUST NOT be altered in the
recurrenceOverrides; it may only be set on the base object.
5.2. Additional reserved JSCalendar properties
This document also reserves two new JSCalendar properties in the
Participant object for use in JMAP Calendars:
5.2.1. scheduleSequence
Type: UnsignedInt (default: 0)
Context: Participant
This is the sequence property of the most recent iTIP response that
has been applied for this participant. It can be compared to the
sequence property in future responses to detect and discard older
responses delivered out of order.
Whenever an event is updated due to an iTIP response, whether by the
server or the client, this property MUST be set appropriately.
5.2.2. scheduleUpdated
Type: UTCDateTime (optional)
Context: Participant
This is the updated property of the most recent iTIP response that
has been applied for this participant. It can be compared to the
updated property in future responses to detect and discard older
responses delivered out of order (if the "scheduleSequence" is the
same).
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Whenever an event is updated due to an iTIP response, whether by the
server or the client, this property MUST be set appropriately.
5.3. Attachments
The Link object, as defined in Section 1.4.11 of
[I-D.ietf-calext-jscalendarbis], with a "rel" property equal to
"enclosure" is used to represent attachments. Instead of mandating
an "href" property, clients may set a "blobId" property instead to
reference a blob of binary data in the account, as per Section 6 of
[RFC8620].
The server MUST translate this to an embedded data: URL [RFC2397]
when sending the event to a system that cannot access the blob.
Servers that support CalDAV access to the same data are recommended
to expose these files as managed attachments [RFC8607].
5.4. Per-user properties
In shared calendars, any top-level property registered in the IANA
registry as "Is Per-User: yes" (see Section 10.8) MUST be stored per-
user. This includes:
* keywords
* color
* freeBusyStatus
* useDefaultAlerts
* alerts
If the user modifies any such properties on a per-occurrence basis
for recurring events then again, these MUST also be stored per-user.
Sharees initially receive the default value for each of these
properties, not whatever value another user may have set.
When writing only per-user properties, the "updated" property MUST
also be stored just for that user if set. When fetching the
"updated" property, the value to return is whichever is later of the
per-user updated time or the updated time of the base event.
5.5. Recurring events
Events may recur, in which case they represent multiple occurrences
or instances. The data store will either contain a single base
event, containing a recurrence rule and/or recurrence overrides; or,
a set of individual instances (when invited to specific occurrences
only).
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The client may ask the server to expand recurrences within a specific
time range in "CalendarEvent/query". This will generate synthetic
ids representing individual instances in the requested time range.
The client can fetch and update the objects using these ids and the
server will make the appropriate changes to the base event.
Synthetic ids do not appear in "CalendarEvent/changes" responses;
only the ids of events as actually stored on the server.
If the user is invited to specific instances then later added to the
base event, "CalendarEvent/changes" will show the ids of all the
individual instances being destroyed and the id for the base event
being created.
5.6. Updating for "this-and-future"
When editing a recurring event, you can either update the base event
(affecting all instances unless overridden) or update an override for
a specific occurrence. To update all occurrences from a specific
point onwards, there are therefore two options: split the event, or
update the base event and override all occurrences before the split
point back to their original values.
5.6.1. Splitting an event
If the event is not scheduled (has no participants), the simplest
thing to do is to duplicate the event, modifying the recurrence rule
of the original so it finishes before the split point, and the
duplicate so it starts at the split point. As per JSCalendar
Section 4.1.2 of [I-D.ietf-calext-jscalendarbis], a "next" and
"first" relation MUST be set on the new objects respectively.
5.6.2. Updating the base event and overriding previous
Splitting an event with participants is problematic, because they
will see two separate changes and may not understand they are
connected.
An alternative approach is to do the following:
1. Update the base event with the changes for "this and future".
2. Create overrides for all occurrences before the split point to
restore the properties to their previous values.
This approach MUST be used if the user does not have the permissions
required to split the event (e.g., if they are not an owner of the
event).
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This approach is RECOMMENDED if making changes to properties other
than "start", "timeZone", or recurrenceRule", as the single event
update is easier for participants to understand.
Modifying the recurrence rule or start date/time zone with this
method is NOT RECOMMENDED. While allowed by the data format
specification, there is poor support in servers for recurrence
overrides that add instances prior to the base event start date, and
so this should be avoided. When making a change to these properties,
the client SHOULD split the event instead, unless it knows all
participants are using software that can handle this type of change.
5.7. CalendarEvent/get
This is a standard "/get" method as described in Section 5.1 of
[RFC8620], with four extra arguments:
*recurrenceOverridesBefore*: UTCDateTime|null
If given, only recurrence overrides with a recurrence id before
this date (when translated into UTC) will be returned.
*recurrenceOverridesAfter*: UTCDateTime|null
If given, only recurrence overrides with a recurrence id on or
after this date (when translated into UTC) will be returned.
*reduceParticipants*: Boolean (default: false)
If true, only participants with the "owner" role or corresponding
to the user's participant identities will be returned in the
"participants" property of the base event and any recurrence
overrides. If false, all participants will be returned.
*timeZone*: TimeZoneId (default "Etc/UTC")
The time zone to use when calculating the "utcStart"/"utcEnd"
property of floating events. This argument has no effect if those
properties are not requested.
A CalendarEvent object is a JSCalendar Event object so may have
arbitrary properties. If the client makes a "CalendarEvent/get" call
with a null or omitted "properties" argument, all properties that are
defined on the JSCalendar Event object in the store are returned
except for "iCalComponent". In addition, the "id", "calendarIds",
"isDraft", and "isOrigin" properties MUST be included on each object.
The "utcStart" and "utcEnd" computed properties are only returned if
explicitly requested. If either are requested, the
"recurrenceOverrides" property MUST NOT be requested (recurrence
overrides cannot be interpreted accurately with just the UTC times).
The "iCalComponent" property is also only returned if explicitly
requested.
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If specific properties are requested from the JSCalendar Event and
the property is not present on the object in the server's store, the
server MUST return the default value if known for that property.
A requested id may represent a server-expanded single instance of a
recurring event if the client asked the server to expand recurrences
in "CalendarEvent/query". In such a case, the server will resolve
any overrides and set the appropriate "start" and "recurrenceId"
properties on the CalendarEvent object returned to the client. The
"recurrenceRule" and "recurrenceOverrides" properties MUST be
returned as null if requested for such an event.
An event with the same uid/recurrenceId may appear in different
accounts. Clients may coalesce the view of such events, but must be
aware that the data may be different in the different accounts due to
per-user properties, difference in permissions, etc.
The "hideAttendees" property of a JSCalendar Event object allows the
event owner(s) to hide the full set of participants when sharing the
event. If this is true, when a non-owner fetches the event the
server MUST only return participants with the "owner" role or
corresponding to the user's participant identities.
The "privacy" property of a JSCalendar Event object allows the
Principal that owns the calendar to override how the event is exposed
to those with whom the calendar is shared. If set to "private", then
when another user fetches the event the server MUST only return
properties that are:
* the basic time and metadata properties of the JSCalendar Event
object as specified in Section 4.4.3 of
[I-D.ietf-calext-jscalendarbis]; or
* properties that are wholly derived from these permitted properties
(i.e., utcStart, utcEnd); or
* Additional CalendarEvent properties not derived from the
JSCalendar Event data (i.e., id, baseEventId, calendarIds,
isDraft, isOrigin).
If "privacy" is set to "secret", the server MUST behave as though the
event does not exist for all users other than the Principal that owns
the calendar.
5.8. CalendarEvent/changes
This is a standard "/changes" method as described in Section 5.2 of
[RFC8620].
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Synthetic ids generated by the server expanding recurrences in
"CalendarEvent/query" do not appear in "CalendarEvent/changes"
responses; only the ids of events as actually stored on the server.
5.9. CalendarEvent/set
This is a standard "/set" method as described in Section 5.3 of
[RFC8620], with the following extra argument:
*sendSchedulingMessages*: Boolean (default: false)
If true then any changes to scheduled events will be sent to all
the participants (if the server is the origin of the event) or
back to the origin (otherwise), as per Section 5.9.2.
An id may represent a server-expanded single instance of a recurring
event if the client asked the server to expand recurrences in
"CalendarEvent/query". When the synthetic id for such an instance is
given, the server MUST process an update as an update to the
recurrence override for that instance on the base event, and a
destroy as removing just that instance.
Clients MUST NOT send an update/destroy to both the base event and a
synthetic instance in a single "/set" request; the result of this is
undefined. Note however, a client may replace a series of explicit
instances (each with the same uid but a different "recurrenceId"
property) with the base event (same uid, no recurrenceId) in a single
"/set" call. (So the "/set" will destroy the existing instances and
create the new base event.) This will happen when someone is
initially invited to a specific instance or instances of a recurring
event, then later invited to the whole series.
If a property is set to null in a create/update, this is equivalent
to omitting/removing the property from the JSCalendar Event object.
Servers MUST enforce the user's permissions as returned in the
"myRights" property of the Calendar objects and reject changes with a
forbidden SetError if not allowed.
The "privacy" property of a JSCalendar Event object allows the
Principal that owns the calendar to override how the event is exposed
to those with whom the calendar is shared. If this is set to
"private", the event may only be destroyed or updated by the owner of
the calendar it is in. Any attempt by another user to modify such an
event MUST be rejected with a forbidden SetError (even if only
modifying per-user properties). If set to "secret", the server MUST
behave as though the event does not exist for all users other than
the Principal that owns the calendar.
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The "privacy" property MUST NOT be set to anything other than
"public" (the default) for events in a calendar that does not belong
to the user (e.g. a shared team calendar, or a calendar shared by
another user). The server MUST reject this with an invalidProperties
SetError.
If omitted on create, the server MUST set the following properties:
* @type MUST be set to "Event"
* uid MUST be set to a new globally unique identifier, such as a
UUID.
* created MUST be set to the current date-time.
If (and only if) the server is the origin of the event (i.e., the
event's "isOrigin" property is true), the "updated" property MUST be
set to the current time by the server whenever an event is created or
updated. If the client tries to set a value for this property it is
not an error, but it MUST be overridden and replaced with the
server's time. If the event is being created and the overridden
"updated" time is now earlier than a client-supplied "created" time,
the "created" time MUST also be overridden to the server's time. If
the server is not the origin of the event it MUST NOT automatically
set an "updated" time, as this can break correct processing of
scheduling messages.
Clients MUST NOT allow users to edit anything other than per-user
properties when the "isOrigin" property is false, even if the
calendar "myRights" allows them to do so. All other properties may
be overwritten when a future update arrives to this event from the
origin (e.g., via an iTIP REQUEST message). Such updates may be
directly applied by the server, or applied at the user's request by a
client if it has access to the data through some other means (e.g.,
the client also has access to the user's email and can parse an iMIP
message).
When updating an event, if all of:
* a property has been changed other than "calendarIds", "isDraft",
"updated" or a per-user property (see Section 5.4); and
* the server is the origin of the event (the "isOrigin" property is
true); and
* the "sequence" property is not explicitly set in the update, or
the given value is less than or equal to the current "sequence"
value on the server;
then the server MUST increment the "sequence" value by one.
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The "method" property MUST NOT be set. Any attempt to do so is
rejected with a standard invalidProperties SetError.
If "utcStart" is set, this is translated into a "start" property
using the server's current time zone information. It MUST NOT be set
in addition to a "start" property and it cannot be set inside
"recurrenceOverrides"; this MUST be rejected with an
invalidProperties SetError.
Similarly, the "utcEnd" property is translated into a "duration"
property if set. It MUST NOT be set in addition to a "duration"
property and it cannot be set inside "recurrenceOverrides"; this MUST
be rejected with an invalidProperties SetError.
The server does not automatically reset the "partipationStatus" or
"expectReply" properties of a Participant when changing other event
details. Clients should either be intelligent about whether the
change invalidates previous RSVPs, or ask the user whether to reset
them.
The server MAY enforce that all events have an owner, for example in
team calendars. If the user tries to create an event without
participants in such a calendar, the server MUST automatically add a
participant with the "owner" role corresponding to one of the user's
ParticipantIdentities (see Section 3).
When creating an event with participants, or adding participants to
an event that previously did not have participants, the server MUST
set the "organizerCalendarAddress" property of the event if not
present. Clients SHOULD NOT set the "organizerCalendarAddress"
property for events when the user adds participants, as the server is
better placed to choose the best address (for example, it might
choose to user a different address per event).
The following extra SetError type is defined:
*noSupportedScheduleMethods*
The server was requested to send scheduling messages, but does not
support any of the methods available for at least one of the
recipients.
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5.9.1. Patching
The JMAP "/set" method allows you to update an object by sending a
patch, rather than having to supply the whole object. When doing so,
care must be taken if updating a property of a CalendarEvent where
the value is itself a PatchObject, e.g. inside "localizations" or
"recurrenceOverrides". In particular, you cannot add a property with
value null to the CalendarEvent using a direct patch on that
property, as this is interpreted instead as a patch to remove the
property.
This is more easily understood with an example. Suppose you have a
CalendarEvent object like so:
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{
"id": "123",
"title": "FooBar team meeting",
"start": "2025-01-08T09:00:00",
"recurrenceRule": {
"@type": "RecurrenceRule",
"frequency": "weekly"
},
"organizerCalendarAddress": "mailto:6489-4f14-a57f-c1@schedule.example.com",
"participants": {
"dG9tQGZvb2Jhci5xlLmNvbQ": {
"@type": "Participant",
"name": "Tom",
"email": "tom@foobar.example.com",
"calendarAddress": "mailto:6489-4f14-a57f-c1@calendar.example.com",
"participationStatus": "accepted",
"roles": {
"attendee": true
}
},
"em9lQGZvb2GFtcGxlLmNvbQ": {
"@type": "Participant",
"name": "Zoe",
"email": "zoe@foobar.example.com",
"calendarAddress": "mailto:zoe@foobar.example.com",
"participationStatus": "accepted",
"roles": {
"owner": true,
"attendee": true,
"chair": true
}
},
"recurrenceOverrides": {
"2025-03-05T09:00:00": {
"start": "2025-03-05T10:00:00",
"participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus":
"declined"
}
}
}
}
Figure 1: A CalendarEvent object
In this example, Tom is normally going to the weekly meeting but has
declined the occurrence on 2025-03-05, which starts an hour later
than normal. Now, if Zoe too were to decline that meeting, she could
update the event by just sending a patch like so:
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[[ "CalendarEvent/set", {
"accountId": "a0x9",
"update": {
"123": {
"recurrenceOverrides/2025-03-05T09:00:00/\
participants~1em9lQGZvb2GFtcGxlLmNvbQ~1participationStatus":
"declined"
}
}
}, "0" ]]
Figure 2: "methodCalls" Property of a JMAP Request. NOTE: '\'
line wrapping per [RFC8792].
This patches the "2025-03-05T09:00:00" PatchObject in
recurrenceOverrides so that it ends up like this:
"recurrenceOverrides": {
"2025-03-05T09:00:00": {
"start": "2025-03-05T10:00:00",
"participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus":
"declined",
"participants/em9lQGZvb2GFtcGxlLmNvbQ/participationStatus":
"declined"
}
}
Figure 3: "recurrenceOverrides" Property in a CalendarEvent Object
Now if Tom were to change his mind and remove his declined status
override (thus meaning he is attending, as inherited from the top-
level event), he might remove his patch from the overrides like so:
[[ "CalendarEvent/set", {
"accountId": "a0x9",
"update": {
"123": {
"recurrenceOverrides/2025-03-05T09:00:00/\
participants~1dG9tQGZvb2Jhci5xlLmNvbQ~1participationStatus": null
}
}
}, "0" ]]
Figure 4: "methodCalls" Property of a JMAP Request. NOTE: '\'
line wrapping per [RFC8792].
However, if you instead want to remove Tom from this instance
altogether, you could not send this patch:
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[[ "CalendarEvent/set", {
"accountId": "a0x9",
"update": {
"123": {
"recurrenceOverrides/2025-03-05T09:00:00/\
participants~1dG9tQGZvb2Jhci5xlLmNvbQ": null
}
}
}, "0" ]]
Figure 5: "methodCalls" Property of a JMAP Request. NOTE: '\'
line wrapping per [RFC8792].
This would mean removing the "participants/dG9tQGZvb2Jhci5xlLmNvbQ"
property at path "recurrenceOverrides" -> "2025-03-05T09:00:00"
inside the object; but this doesn't exist. We actually want to add
this property and make it map to null. The client must instead send
the full object that contains the property mapping to null, like so:
[[ "CalendarEvent/set", {
"accountId": "a0x9",
"update": {
"123": {
"recurrenceOverrides/2025-03-05T09:00:00": {
"start": "2025-03-05T10:00:00",
"participants/em9lQGZvb2GFtcGxlLmNvbQ/participationStatus":
"declined",
"participants/dG9tQGZvb2Jhci5xlLmNvbQ": null
}
}
}
}, "0" ]]
Figure 6: "methodCalls" Property of a JMAP Request
5.9.2. Sending invitations and responses
If "sendSchedulingMessages" is true, the server MUST send appropriate
iTIP [RFC5546] scheduling messages after successfuly creating,
updating or destroying a calendar event.
When determining which scheduling messages to send, the server must
first establish whether it is the *origin* of the event, as described
in the "isOrigin" property.
The server sends the scheduling message via iTIP [RFC5546] to the
"calendarAddress" property of a participant (if the server is the
origin) or the "organizerCalendarAddress" property of the event
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(otherwise). If any of the recipients do not have a calendar address
the server can send to, the server MUST reject the change with a
noSupportedScheduleMethods SetError.
If the server is the origin of the event it MUST NOT send messages to
any participant where it will receive the message back in the same
account (i.e. it must not send messages to the owner of the calendar
the event is already on).
If sending via iMIP [RFC6047], the server MAY choose to only send
updates it deems "essential" to avoid flooding the recipient's email
with changes they do not care about. For example, changes to the
participation status of another participant, or changes to events
solely in the past may be omitted.
5.9.2.1. REQUEST
When the server is the origin for the event, a REQUEST message
([RFC5546], Section 3.2.2) is sent to all current participants
(except those corresponding to the owner of the calendar) if either:
* The event is being created; or
* Any non per-user property (see Section 5.4) is updated on the
event (including adding/removing participants), except if just
modifying the recurrenceOverrides such that CANCEL messages are
generated (see the next section).
Note, if the only change is adding an additional instance (not
generated by the event's recurrence rule) to the recurrenceOverrides,
this MAY be handled via sending an ADD message (Section 3.2.4 of
[RFC5546]) for the single instance rather than a REQUEST message for
the base event. However, for interoperability reasons this is not
recommended due to poor support in the wild for this type of message.
The server MUST ensure participants are only sent information about
recurrence instances they are added to when sending scheduling
messages for recurring events. If the participant is not invited to
the full recurring event but only individual instances, scheduling
messages MUST be sent for just those expanded occurrences
individually. If a participant is invited to a recurring event, but
removed via a recurrence override from a particular instance, any
scheduling messages to this participant MUST return the instance as
"excluded" (if it matches a recurrence rule for the event) or omit
the instance entirely (otherwise).
If the event's "hideAttendees" property is set to true, the recipient
MUST be the only attendee in the message; all others are omitted.
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5.9.2.2. CANCEL
When the server is the origin for the event, a CANCEL message
([RFC5546], Section 3.2.5) is sent if any of:
* A participant is removed from either the base event or a single
instance (the message is only sent to this participant; remaining
participants will get a REQUEST, as described above).
* The event is destroyed.
* An exclusion is added to recurrenceOverrides to remove an instance
generated by the event's recurrence rule.
* An additional instance (not generated by the event's recurrence
rule) is removed from the recurrenceOverrides.
In each of the latter 3 cases, the message is sent to all
participants (except those corresponding to the owner of the
calendar).
5.9.2.3. REPLY
When the server is *not* the origin for the event, a REPLY message
([RFC5546], Section 3.2.3) is sent for every participant
corresponding to one of the user's ParticipantIdentitities in the
account if any of the following changes are made:
* The "participationStatus" property of the participant is changed,
either for the base event or a specific instance, to any value
other than "needs-action".
* The event is created and the participationStatus is not "needs-
action".
* The event is destroyed and the participationStatus was not "needs-
action".
If the participationStatus property is changed for just a single
instance of the event (i.e., set in recurrenceOverrides), the REPLY
message SHOULD be sent for just that recurrence id.
5.10. CalendarEvent/copy
This is a standard "/copy" method as described in Section 5.4 of
[RFC8620].
5.11. CalendarEvent/query
This is a standard "/query" method as described in Section 5.5 of
[RFC8620], with two extra arguments:
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*expandRecurrences*: Boolean (default: false)
If true, the server will expand any recurring event. If true, the
filter MUST be just a FilterCondition (not a FilterOperator) and
MUST include both a "before" and "after" property. This ensures
the server is not asked to return an infinite number of results.
*timeZone*: TimeZoneId
The time zone for before/after filter conditions (default: "Etc/
UTC")
If expandRecurrences is true, a separate id will be returned for each
instance of a recurring event that matches the query. This synthetic
id is opaque to the client, but uniquely identifies the base event id
+ recurrence id within the account, allowing the server to resolve
these for "/get" and "/set" operations. Otherwise, a single id will
be returned for matching recurring events that represents the entire
event.
There is no necessary correspondence between the ids of different
instances of the same expanded event.
The following additional error may be returned instead of the
"CalendarEvent/query" response:
expandDurationTooLarge: The query has expandRecurrences set to true,
and the duration between the "before" and "after" properties exceeds
the maxExpandedQueryDuration limit (as found in the account
capabilities).
cannotCalculateOccurrences: The server cannot expand a recurrence
required to return the results for this query.
5.11.1. Filtering
A *FilterCondition* object has the following properties, any of which
may be omitted:
*inCalendar*: Id
A Calendar id. An event must be in this calendar to match the
condition.
*after*: LocalDateTime
The end of the event, or any recurrence of the event, in the time
zone given as the "timeZone" argument, must be after this date to
match the condition.
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*before*: LocalDateTime
The start of the event, or any recurrence of the event, in the
time zone given as the "timeZone" argument, must be before this
date to match the condition.
*text*: String
Looks for the text in the "title", "description", "locations"
(matching name/description), "participants" (matching name/email)
and any other textual properties of the event or any recurrence of
the event.
*title*: String
Looks for the text in the "title" property of the event, or the
overridden "title" property of a recurrence.
*description*: String
Looks for the text in the "description" property of the event, or
the overridden "description" property of a recurrence.
*location*: String
Looks for the text in the "locations" property of the event
(matching name/description of a location), or the overridden
"locations" property of a recurrence.
*owner*: String
Looks for the text in the name or email fields of a participant in
the "participants" property of the event, or the overridden
"participants" property of a recurrence, where the participant has
a role of "owner".
*attendee*: String
Looks for the text in the name or email fields of a participant in
the "participants" property of the event, or the overridden
"participants" property of a recurrence, where the participant has
a role of "attendee".
*uid*: String
The uid of the event is exactly the given string.
If expandRecurrences is true, all conditions must match against the
same instance of a recurring event for the instance to match. If
expandRecurrences is false, all conditions must match, but they may
each match any instance of the event.
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If zero properties are specified on the FilterCondition, the
condition MUST always evaluate to true. If multiple properties are
specified, ALL must apply for the condition to be true (it is
equivalent to splitting the object into one-property conditions and
making them all the child of an AND filter operator).
The exact semantics for matching String fields is *deliberately not
defined* to allow for flexibility in indexing implementation, subject
to the following:
* Text should be matched in a case-insensitive manner.
* Text contained in either (but matched) single or double quotes
should be treated as a *phrase search*, that is a match is
required for that exact sequence of words, excluding the
surrounding quotation marks. Use \", \' and \\ to match a literal
", ' and \ respectively in a phrase.
* Outside of a phrase, white-space should be treated as dividing
separate tokens that may be searched for separately in the event,
but must all be present for the event to match the filter.
* Tokens may be matched on a whole-word basis using stemming (so for
example a text search for bus would match "buses" but not
"business").
5.11.2. Sorting
The following properties MUST be supported for sorting:
* start
* uid
* recurrenceId
The following properties SHOULD be supported for sorting:
* created
* updated
5.12. CalendarEvent/queryChanges
This is a standard "/queryChanges" method as described in Section 5.6
of [RFC8620].
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5.13. CalendarEvent/parse
This method allows the client to parse blobs as iCalendar files
[RFC5545] to get CalendarEvent objects. This can be used to parse,
display, and import information from iCalendar files without having
to implement iCalendar parsing in the client. Server support for
this is optional, and indicated via the
urn:ietf:params:jmap:calendars:parse capability, as per
Section 1.5.3.
The following metadata properties on the CalendarEvent objects will
be null if requested:
* id
* baseEventId
* calendarIds
* isDraft
* isOrigin
The "CalendarEvent/parse" method takes the following arguments:
*accountId*: Id
The id of the account to use.
*blobIds*: Id[]
The ids of the blobs to parse.
*properties*: String[]
If supplied, only the properties listed in the array are returned
for each CalendarEvent object. If omitted, defaults to all the
properties.
The response object contains the following arguments:
*accountId*: Id
The id of the account used for the call.
*parsed*: Id[CalendarEvent[]]|null
A map of blob ids to parsed CalendarEvent objects representations
for each successfully parsed blob, or null if none.
*notFound*: Id[]|null
A list of blob ids given that could not be found, or null if none.
*notParsable*: Id[]|null
A list of blob ids given that corresponded to blobs that could not
be parsed as CalendarEvents, or null if none.
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Parsed iCalendars are to be converted into CalendarEvent objects
following the process defined in the JSCalendar: Converting from and
to iCalendar (https://datatracker.ietf.org/doc/draft-ietf-calext-
jscalendar-icalendar) document.
6. Alerts
Alerts may be specified on events as described in Section 4.5 of
[I-D.ietf-calext-jscalendarbis].
Alerts MUST only be triggered for events in calendars where the user
is subscribed.
When an alert with an "email" action is triggered, the server MUST
send an email to the user to notify them of the event. The content
of the email is implementation specific. Clients MUST NOT perform an
action for these alerts.
When an alert with a "display" action is triggered, clients should
display an alert in a platform-appropriate manner to the user to
remind them of the event. Clients with a full offline cache of
events may choose to calculate when alerts should trigger locally.
Alternatively, they can subscribe to push events from the server.
6.1. Default alerts
If the "useDefaultAlerts" property of an event is true, the alerts
are taken from the "defaultAlertsWithTime" or
"defaultAlertsWithoutTime" property of all Calendars (see Section 4)
the event is in, rather than the "alerts" property of the
CalendarEvent.
When using default alerts, the "alerts" property of the event is
ignored except for the following:
* The "acknowledged" time for an alert is stored here when a default
alert for the event is dismissed. The id of the alert MUST be the
same as the id of the default alert in the calendar. See
Section 6.2 on acknowledging alerts.
* If an alert has a "relatedTo" property where the parent is the id
of one of the calendar default alerts, it is processed as normal
and not ignored. This is to support snoozing default alerts; see
Section 6.3.
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6.2. Acknowledging an alert
To dismiss an alert, clients set the "acknowledged" property of the
Alert object to the current date-time. If the alert was a calendar
default, it may need to be added to the event at this point in order
to acknowledge it. When other clients fetch the updated
CalendarEvent they SHOULD automatically dismiss or suppress duplicate
alerts (alerts with the same alert id that triggered on or before the
"acknowledged" date-time) and alerts that have been removed from the
event.
Setting the "acknowledged" property MUST NOT create a new recurrence
override. For a recurring calendar object, the "acknowledged"
property of the parent object MUST be updated, unless the alert is
already overridden in the "recurrenceOverrides" property.
6.3. Snoozing an alert
Users may wish to dismiss an alert temporarily and have it come back
after a specific period of time. To do this, clients MUST:
1. Acknowledge the alert as described in Section 6.2.
2. Add a new alert to the event that has an AbsoluteTrigger
specifying the date-time when the alert will trigger again. Add
a "relatedTo" property to the new alert, setting the "snooze"
relation to point to the original alert. This MUST NOT create a
new recurrence override; it is added to the same "alerts"
property that contains the alert that was acknowledged in step 1.
When acknowledging a snoozed alert (i.e. one with a "snooze"
relatedTo pointing to the original alert), the client should delete
the alert rather than setting the "acknowledged" property.
6.4. Push events
Servers that support the urn:ietf:params:jmap:calendars capability
MUST support registering for the pseudo-type "CalendarAlert" in push
subscriptions and event source connections, as described in
[RFC8620], Sections 7.2 and 7.3.
If requested, a CalendarAlert notification will be pushed whenever an
alert is triggered for the user. For Event Source connections, this
notification is pushed as an event called "calendarAlert".
A *CalendarAlert* object has the following properties:
*@type*: String
This MUST be the string "CalendarAlert".
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*accountId*: Id
The account id for the calendar in which the alert triggered.
*calendarEventId*: Id
The CalendarEvent id for the alert that triggered. Note, for a
recurring event this is the id of the base event, never a
synthetic id for a particular instance.
*uid*: String
The "uid" property of the CalendarEvent for the alert that
triggered.
*recurrenceId*: LocalDateTime|null
The recurrenceId for the instance of the event for which this
alert is being triggered, or null if the event is not recurring.
*alertId*: String
The id for the alert that triggered.
7. Calendar Event Notifications
The CalendarEventNotification data type represents changes to events
in calendars that the user is subscribed to where the change was not
explicitly made by the user themself. CalendarEventNotifications are
only created by the server; users cannot create them explicitly.
They are stored in the same Account as the CalendarEvent that was
changed.
Clients may present the list of notifications to the user and allow
the user to dismiss them. To dismiss a notification, use a standard
"/set" call to destroy it.
The server should create a CalendarEventNotification whenever an
event is added, updated or destroyed by someone else. This includes:
* When an event is edited directly by another user on a shared
calendar.
* If the server chooses to auto-process scheduling requests, such as
an iTIP message. Note, whether to auto-process such messages is
an implementation policy.
The CalendarEventNotification does not have any per-user data. A
single instance may therefore be maintained on the server for all
users with whom the calendar is shared. The server need only keep
track of which users have yet to destroy the notification.
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The server MAY limit the maximum number of notifications it will
store for a user. When the limit is reached, any new notification
will cause the previously oldest notification to be automatically
deleted.
The server MAY coalesce notifications if appropriate or remove
notifications after a certain period of time or that it deems are no
longer relevant.
A *CalendarEventNotification* object has the following properties:
*id*: Id
The id of the CalendarEventNotification.
*created*: UTCDateTime
The time this notification was created.
*changedBy*: Person
Who made the change. The Person object has the following
properties:
*name*: String
The name of the person who made the change.
*email*: String|null
The email of the person who made the change, or null if no
email is available.
*principalId*: Id|null
The id of the Principal corresponding to the person who made
the change, if any. This will be null if the change was due to
an entity outside of this user's organisation, e.g. an iTIP
invitation from an external person.
*calendarAddress*: String|null
The calendarAddress URI of the person who made the change, if
any. This may be set if the change was made due to receving a
scheduling message, such as an iTIP message, in addition to
changes made by internal users.
*comment*: String|null
Comment sent along with the change by the user that made it. (e.g.
COMMENT property in an iTIP message), if any.
*type*: String
This MUST be one of:
* "created"
* "updated"
* "destroyed"
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*calendarEventId*: Id
The id of the CalendarEvent that this notification is about.
*isDraft*: Boolean (created/updated only)
True if the event is a draft.
*event*: JSCalendar Event
The data before the change (if updated or destroyed), or the data
after creation (if created).
*eventPatch*: PatchObject (updated only)
A patch encoding the change between the data in the event
property, and the data after the update.
If the change only affects a single instance of a recurring event,
the server MAY set the event and eventPatch properties for just that
instance; the calendarEventId MUST still be for the base event.
7.1. CalendarEventNotification/get
This is a standard "/get" method as described in Section 5.1 of
[RFC8620].
7.2. CalendarEventNotification/changes
This is a standard "/changes" method as described in Section 5.2 of
[RFC8620].
7.3. CalendarEventNotification/set
This is a standard "/set" method as described in Section 5.3 of
[RFC8620].
Only destroy is supported; any attempt to create/update MUST be
rejected with a forbidden SetError.
7.4. CalendarEventNotification/query
This is a standard "/query" method as described in Section 5.5 of
[RFC8620].
7.4.1. Filtering
A *FilterCondition* object has the following properties:
*after*: UTCDateTime|null
The creation date must be on or after this date to match the
condition.
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*before*: UTCDateTime|null
The creation date must be before this date to match the condition.
*type*: String
The "type" property must be the same to match the condition.
*calendarEventIds*: Id[]|null
A list of event ids. The "calendarEventId" property of the
notification must be in this list to match the condition.
7.4.2. Sorting
The "created" property MUST be supported for sorting.
7.5. CalendarEventNotification/queryChanges
This is a standard "/queryChanges" method as described in Section 5.6
of [RFC8620].
8. Examples
For brevity, in the following examples only the "methodCalls"
property of the Request object, and the "methodResponses" property of
the Response object is shown.
8.1. Fetching initial data
A user has authenticated and the client has fetched the JMAP Session
object. It finds a single Account with the
urn:ietf:params:jmap:calendars capability, with id "a0x9", and wants
to display all the calendar information for January 2023 in the
Australia/Melbourne time zone. It might make the following request:
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[
["Calendar/get", {
"accountId": "a0x9"
}, "0"],
["ParticipantIdentity/get", {
"accountId": "a0x9"
}, "1"],
["CalendarEvent/query", {
"accountId": "a0x9",
"timeZone": "Australia/Melbourne",
"filter": {
"after": "2023-01-01T00:00:00",
"before": "2023-02-01T00:00:00"
}
}, "2"],
["CalendarEvent/get", {
"accountId": "a0x9",
"#ids": {
"resultOf": "2",
"name": "CalendarEvent/query",
"path": "/ids"
}
}, "3"]
]
Figure 7: "methodCalls" Property of a JMAP Request
The server might respond with something like:
[
["Calendar/get", {
"accountId": "a0x9",
"list": [{
"id": "062adcfa-105d-455c-bc60-6db68b69c3f3",
"name": "Private",
"sortOrder": 12,
"isDefault": false,
"defaultAlertsWithTime": null,
...
}, {
"id": "3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662",
"name": "Work",
"sortOrder": 4,
"isDefault": true,
"defaultAlertsWithTime": {
"631BE24C-A3B6-11EC-BF4C-B027680D752E": {
"@type": "Alert",
"action": "display",
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"trigger": {
"@type": "OffsetTrigger",
"offset": "-PT1H",
"relativeTo": "start"
}
}
},
...
}],
"notFound": [],
"state": "~506"
}, "0"],
["ParticipantIdentity/get", {
"accountId": "a0x9",
"list": [{
"id": "3",
"name": "Jane Doe",
"calendarAddress": "mailto:jane@example.com",
"isDefault": true
}],
"notFound": [],
"state": "lgkf:98144:aae"
}, "1"],
["CalendarEvent/query", {
"accountId": "a0x9",
"canCalculateChanges": false,
"position": 0,
"queryState": "~206",
"ids": [
"E-01c9626e-1490-43df-a34f-457021256281",
"E-07a2b89d-96b6-4920-982a-54fdf0a386ce",
...
]
}, "2"],
["CalendarEvent/get", {
"accountId": "a0x9",
"list": [{
"id": "E-01c9626e-1490-43df-a34f-457021256281",
"calendarIds": {
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662": true
},
"title": "Q1 All hands",
"start": "2023-01-09T10:00:00",
"duration": "PT1H",
"timeZone": "Australia/Sydney",
...
}, ...],
"notFound": [],
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"state": "$$/413/206"
}, "3"]
]
Figure 8: "methodResponses" Property of a JMAP Response
The client now has everything it needs to display that month in full.
8.2. Creating an event
Suppose the user asks the client to create a new event. The client
should default to adding it to the "Work" calendar, as this is the
default calendar for the user, unless it has information to make a
more informed decision. (e.g. The client may have a feature to
automatically choose the calendar based on the time of day, and the
user indicates the event is at 7pm, so it knows to default to
"Private".)
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[["CalendarEvent/set", {
"accountId": "a0x9",
"create": {
"k559": {
"uid": "5d5776f6-ff8e-4bfd-ab3e-fe2fe5d4fa91",
"calendarIds": {
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662": true
},
"title": "Party at Pete’s",
"start": "2023-02-03T19:00:00",
"duration": "PT3H0M0S",
"timeZone": "Australia/Melbourne",
"showWithoutTime": false,
"participants": {
"1": {
"@type": "Participant",
"name": "Jane Doe",
"calendarAddress": "mailto:jane@example.com",
"kind": "individual",
"roles": {
"attendee": true,
"owner": true
},
"participationStatus": "accepted",
"expectReply": false
},
"2": {
"@type": "Participant",
"name": "Joe Bloggs",
"calendarAddress": "mailto:joe@example.com",
"kind": "individual",
"roles": {
"attendee": true
},
"participationStatus": "needs-action",
"expectReply": true
}
},
"mayInviteSelf": false,
"mayInviteOthers": false,
"useDefaultAlerts": false,
"alerts":null
}
},
"sendSchedulingMessages": true
}, "0"]]
Figure 9: "methodCalls" Property of a JMAP Request
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As the event has participants, the server sets an
"organizerCalendarAddress" property. This server uses a special
email address for receiving iMIP RSVPs ([RFC5546]) rather than just
receiving them at the owner's regular email address. The response
may look something like this:
[["CalendarEvent/set", {
"accountId": "a0x9",
"created": {
"k559": {
"id": "E-5d5776f6-ff8e-4bfd-ab3e-fe2fe5d4fa91",
"isOrigin": true,
"@type": "Event",
"created": "20221005T20:42:13Z",
"updated": "20221005T20:42:13Z",
"sequence": 1,
"organizerCalendarAddress": "mailto:3e87-1b18bb5e6b4@itip.example.com"
}
},
...
}, "0"]]
Figure 10: "methodResponses" Property of a JMAP Response. NOTE:
'\' line wrapping per [RFC8792].
8.3. Snoozing an alert
The client is connected to the event source and receives a push:
{
"@type": "CalendarAlert",
"accountId": "a0x9",
"calendarEventId": "E-7e93e3ee-4e6e-408a-9adc-cbaf1dbd0a3f",
"uid": "b6f7e27b-5872-4b52-b457-0242541bb01c",
"recurrenceId": null,
"alertId": "7519a951-1e6f-4a6c-b08b-20dd2e5a89cd"
}
Figure 11: Object Received via Push Connection
Not finding this event in its local cache, the client fetches the
information for this event that it needs to show the alert by making
the following request:
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[["CalendarEvent/get", {
"accountId": "a0x9",
"ids":["E-7e93e3ee-4e6e-408a-9adc-cbaf1dbd0a3f"],
"properties": ["calendarIds", "title", "start",
"timeZone", "useDefaultAlerts", "alerts"]
}, "0"]]
Figure 12: "methodCalls" Property of a JMAP Request
In response it receives:
[["CalendarEvent/get", {
"accountId": "a0x9",
"list": [{
"id": "E-7e93e3ee-4e6e-408a-9adc-cbaf1dbd0a3f",
"calendarIds": {
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662": true
},
"title": "Team catchup",
"start": "2023-02-10T17:00:00",
"timeZone": "America/New_York",
"useDefaultAlerts": false,
"alerts": {
"7519a951-1e6f-4a6c-b08b-20dd2e5a89cd": {
"@type": "Alert",
"action": "display",
"trigger": {
"@type": "OffsetTrigger",
"relativeTo": "start",
"offset": "-PT1H"
}
}
}
}],
"notFound": [],
"state": "$$/414/208"
}, "0"]]
Figure 13: "methodResponses" Property of a JMAP Response
The client displays an alert in a platform-appropriate manner.
Presuming the user here is in the Australia/Melbourne time zone, this
might look something like:
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+----------------------------------------+
| |
| Reminder: Team catchup |
| Today at 10am (in 1 hour) |
| [Snooze\/] |
+----------------------------------------+
Figure 14: Notification Shown to User for a Calendar Alert
The user snoozes the notification for 30 minutes. The client
dismisses the current notification and sends an update to the event
to the server:
[
["CalendarEvent/set", {
"accountId": "a0x9",
"update": {
"E-01c9626e-1490-43df-a34f-457021256281": {
"alerts/7519a951-1e6f-4a6c-b08b-20dd2e5a89cd\
/acknowledged": "2023-02-10T23:00:29Z",
"alerts/86b0-318b8291045f": {
"@type": "Alert",
"action": "display",
"trigger": {
"@type": "AbsoluteTrigger",
"when": "2023-02-10T23:30:00Z",
"relatedTo": {
"7519a951-1e6f-4a6c-b08b-20dd2e5a89cd": {
"@type": "Relation",
"relation": {
"snooze": true
}
}
}
}
}
}
}
}, "0"]
]
Figure 15: "methodCalls" Property of a JMAP Request. NOTE: '\'
line wrapping per [RFC8792].
Any other connected client will receive a push, sync the change and
dismiss any duplicate alert. After the snooze time has elapsed, the
new alert will trigger.
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8.4. Changing the default calendar
The client tries to change the default calendar from "Work" to
"Private" (and makes no other change):
[["Calendar/set", {
"accountId": "a0x9",
"onSuccessSetIsDefault": "062adcfa-105d-455c-bc60-6db68b69c3f3"
}, "0"]]
Figure 16: "methodCalls" Property of a JMAP Request
The server allows the change, returning the following response:
[["Calendar/set", {
"accountId": "a0x9",
"updated": {
"062adcfa-105d-455c-bc60-6db68b69c3f3": {
"isDefault": true
},
"3ddf2ad7-0e0c-4fb5-852d-f0ff56f3c662": {
"isDefault": false
}
}
}, "0"]]
Figure 17: "methodResponses" Property of a JMAP Response
8.5. Parsing an iCalendar file
The client makes a request to parse the calendar event from a blob id
representing an icalendar file:
[[ "CalendarEvent/parse", {
"accountId": "a0x9",
"blobIds": ["Ge682d5d7aad50b3a4f7180a7ed9276476485ea52"]
}, "c1"]]
Figure 18: "methodCalls" Property of a JMAP Request
The server responds:
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[[ "CalendarEvent/parse", {
"accountId": "a0x9",
"parsed": {
"Ge682d5d7aad50b3a4f7180a7ed9276476485ea52": [{
"@type": "Event",
"method": "publish",
"prodId": "-//IETF//datatracker.ietf.org ical agenda//EN",
"uid": "ietf-119-16811-jmap",
"sequence": 2,
"updated": "2024-02-09T22:49:26Z",
"start": "2024-03-19T13:00:00",
"duration": "PT2H",
"timeZone": "Australia/Brisbane",
"showWithoutTime": false,
"title": "jmap - JSON Mail Access Protocol",
"freeBusyStatus": "busy",
"descriptionContentType": "text/plain",
"description": "Session II\n\nRemember to sign the blue sheets!",
"locations": {
"eec47e7589ce131d6331b10383f89f91f8d4a4ef": {
"@type": "Location",
"name": "P3, Brisbane Convention Centre"
}
},
"status": "confirmed"
}]
},
"notFound": null,
"notParsable": null
}, "c1"]]
Figure 19: "methodResponses" Property of a JMAP Response
If the blob id had not been found, the server would have responded:
[[ "CalendarEvent/parse", {
"accountId": "a0x9",
"notFound": ["Ge682d5d7aad50b3a4f7180a7ed9276476485ea52"]
}, "c1" ]]
Figure 20: "methodResponses" Property of a JMAP Response
If the blob id had been found but was not parsable, the server would
have responded:
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[[ "CalendarEvent/parse", {
"accountId": "a0x9",
"notParsable": ["Ge682d5d7aad50b3a4f7180a7ed9276476485ea52"]
}, "c1" ]]
Figure 21: "methodResponses" Property of a JMAP Response
9. Security Considerations
All security considerations of JMAP [RFC8620] and JSCalendar
[I-D.ietf-calext-jscalendarbis] apply to this specification.
Additional considerations specific to the data types and
functionality introduced by this document are described in the
following subsections.
9.1. Privacy
Calendars often contain the precise movements, activities, and
contacts of people; all intensely private data. Privacy leaks can
have real world consequences, and calendar servers and clients MUST
be mindful of the need to keep all data secure.
Servers MUST enforce the ACLs set on calendars to ensure only
authorised data is shared. The additional restrictions specified by
the "privacy" property of a JSCalendar Event object (see
Section 4.4.3 of [I-D.ietf-calext-jscalendarbis]) MUST also be
enforced.
Users may have multiple Participant Identities that they use for
areas of their life kept private from one another. Using one
identity with an event MUST NOT leak the existence of any other
identity. For example, sending an RSVP from identity
worklife@example.com MUST NOT reveal anything about another identity
present in the account such as privatelife@example.org.
Severs SHOULD enforce that invitations sent to external systems are
only transmitted via secure encrypted and signed connections to
protect against eavesdropping and modification of data.
9.2. Spoofing
When receiving events and updates from external systems, it can be
hard to verify that the identity of the author is who they claim to
be. When receiving events via email, DKIM [RFC6376] and S/MIME
[RFC8551] are two mechanisms that may be used to verify certain
properties about the email data, which can be correlated with the
event information.
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9.3. Denial-of-service
There are many ways in which a calendar user can make a request
liable to cause a calendar server to spend an inordinate amount of
processing time. Care must be taken to limit resources allocated to
any one user to ensure the system does not become unresponsive. The
following subsections list particularly hazardous areas.
9.3.1. Expanding Recurrences
Recurrence rules can be crafted to occur as frequently as every
second. Servers MUST be careful to not allow resources to be
exhausted when expanding, and limit the number of expansions they
will create. Equally, rules can be generated that never create any
occurrences at all. Servers MUST be careful to limit the work spent
iterating in search of the next occurrence.
9.3.2. Firing alerts
An alert firing for an event can cause a notification to be pushed to
the user's devices, or to send them an email. Servers MUST rate
limit the number of alerts sent for any one user. The combination of
recurring events with multiple alerts can in particular define
unreasonably frequent alerts, leading to denial of service for either
the server processing them or the user's devices receiving them.
Similarly, clients generating alerts from the data on device must
take the same precautions.
The "email" alert type (see Section 4.5.1 of
[I-D.ietf-calext-jscalendarbis]) causes an email to be sent when
triggered. Clients MUST ignore this alert type; the email is sent
only by the calendar server. There is no mechanism in JSCalendar to
specify a particular email address: the server MUST only allow alerts
to be sent to an address it has verified as belonging to the user to
avoid this being used as a spamming vector.
9.3.3. Load spikes
Since most events are likely to start on the hour mark, a large spike
of activity is often seen at these times, with particularly large
spikes at certain common times in the time zone of the server's user
base. In particular, a large number of alerts (across different
users and events) will be triggered at the same time. Servers may
mitigate this somewhat by adding jitter to the triggering of the
alerts; it is RECOMMENDED to fire them slightly early rather than
slightly late if needed to spread load.
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9.4. Spam
Invitations received from an untrusted source may be spam. If this
is added to the user's calendar automatically it can be very
obtrusive, especially if it is a recurring event that now appears
every day. It could also be used to attempt to phish the user, or
cause them to physically go to a location included in the event.
Incoming invitations to events should be subject to spam scanning,
and suspicious events should not be added to the calendar
automatically.
Servers should strip any alerts on invitations when adding to the
user's calendar; the "useDefaultAlerts" property should be set
instead to apply the user's preferences.
Similarly, a malicious user may use a calendar system to send spam by
inviting people to an event. Outbound scheduling messages should be
subject to all the same controls used on outbound email systems, and
rate limited as appropriate. A rate limit on the number of distinct
recipients as well as overall messages is recommended.
10. IANA Considerations
10.1. JMAP Capability Registration for "calendars"
IANA will register the "calendars" JMAP Capability as follows:
Capability Name: urn:ietf:params:jmap:calendars
Specification document: this document
Intended use: common
Change Controller: IETF
Security and privacy considerations: this document, Section 1.5.1
10.2. JMAP Capability Registration for "principals:availability"
IANA will register the "principals:availability" JMAP Capability as
follows:
Capability Name: urn:ietf:params:jmap:principals:availability
Specification document: this document
Intended use: common
Change Controller: IETF
Security and privacy considerations: this document, Section 1.5.2
10.3. JMAP Data Type Registration for "Calendar"
IANA will register "Calendar" in the "JMAP Data Types" registry as
follows:
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Type Name: Calendar
Can reference blobs: no
Can Use for State Change: yes
Capability: urn:ietf:params:jmap:calendars
Specification document: this document
10.4. JMAP Data Type Registration for "CalendarEvent"
IANA will register "CalendarEvent" in the "JMAP Data Types" registry
as follows:
Type Name: CalendarEvent
Can reference blobs: yes
Can Use for State Change: yes
Capability: urn:ietf:params:jmap:calendars
Specification document: this document
10.5. JMAP Data Type Registration for "CalendarEventNotification"
IANA will register "CalendarEventNotification" in the "JMAP Data
Types" registry as follows:
Type Name: CalendarEventNotification
Can reference blobs: no
Can Use for State Change: yes
Capability: urn:ietf:params:jmap:calendars
Specification document: this document
10.6. JMAP Data Type Registration for "ParticipantIdentity"
IANA will register "ParticipantIdentity" in the "JMAP Data Types"
registry as follows:
Type Name: ParticipantIdentity
Can reference blobs: no
Can Use for State Change: yes
Capability: urn:ietf:params:jmap:calendars
Specification document: this document
10.7. JMAP Error Codes Registry
The following subsections register some new error codes in the "JMAP
Error Codes" registry, as defined in [RFC8620].
10.7.1. calendarHasEvent
JMAP Error Code: calendarHasEvent
Intended use: common
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Change controller: IETF
Reference: This document, Section 4.3
Description: The Calendar has at least one CalendarEvent assigned to
it, and the "onDestroyRemoveEvents" argument was false.
10.7.2. noSupportedScheduleMethods
JMAP Error Code: noSupportedScheduleMethods
Intended use: common
Change controller: IETF
Reference: This document, Section 5.9
Description: The server was requested to send scheduling messages,
but does not support any of the methods available for at least one
of the recipients.
10.7.3. expandDurationTooLarge
JMAP Error Code: expandDurationTooLarge
Intended use: common
Change controller: IETF
Reference: This document, Section 5.11
Description: The query has expandRecurrences set to true, and the
duration between the "before" and "after" properties exceeds the
maxExpandedQueryDuration limit.
10.7.4. cannotCalculateOccurrences
JMAP Error Code: cannotCalculateOccurrences
Intended use: common
Change controller: IETF
Reference: This document, Section 5.11
Description: The server cannot expand a recurrence required to
return the results for the requested query.
10.8. Update to the JSCalendar Properties Registry
IANA will update the "JSCalendar Properties" registry, originally
created in Section 8.2 of [RFC8984], to add a new column called "Is
Per-User". The value in this column for each entry MUST be either
"yes" or "no", indicating whether each user with whom the object is
shared should be able to set their own value for this property
without affecting the value for other users.
10.8.1. Update to "JSCalendar Properties" Registry Template
An additional field is added to the template:
Is Per-User
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10.8.2. Initial values for existing registrations
IANA will set "Is per-user: yes" on the following property
registrations:
* keywords
* color
* freeBusyStatus
* useDefaultAlerts
* alerts
All other existing registrations will have "Is per-user: no".
10.9. JSCalendar Property Registrations
IANA will register the following additional properties in the
JSCalendar Properties Registry.
10.9.1. id
Property Name: id
Property Type: Not applicable
Property Context: Event, Task
Intended Use: Reserved
Is per-user: no
10.9.2. baseEventId
Property Name: baseEventId
Property Type: Not applicable
Property Context: Event, Task
Intended Use: Reserved
Is per-user: no
10.9.3. calendarIds
Property Name: calendarIds
Property Type: Not applicable
Property Context: Event, Task
Intended Use: Reserved
Is per-user: no
10.9.4. isDraft
Property Name: isDraft
Property Type: Not applicable
Property Context: Event, Task
Intended Use: Reserved
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Is per-user: no
10.9.5. isOrigin
Property Name: isOrigin
Property Type: Not applicable
Property Context: Event, Task
Intended Use: Reserved
Is per-user: no
10.9.6. utcStart
Property Name: utcStart
Property Type: Not applicable
Property Context: Event, Task
Intended Use: Reserved
Is per-user: no
10.9.7. utcEnd
Property Name: utcEnd
Property Type: Not applicable
Property Context: Event, Task
Intended Use: Reserved
Is per-user: no
10.9.8. useDefaultAlerts
Property Name: useDefaultAlerts
Property Type: Not applicable
Property Context: Event
Intended Use: Reserved
Is per-user: yes
10.9.9. mayInviteSelf
Property Name: mayInviteSelf
Property Type: Boolean (default: false)
Property Context: Event, Task
Reference: This document, Section 5.1.1.
Intended Use: Common
Is per-user: no
10.9.10. mayInviteOthers
Property Name: mayInviteOthers
Property Type: Boolean (default: false)
Property Context: Event, Task
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Reference: This document, Section 5.1.2.
Intended Use: Common
Is per-user: no
10.9.11. hideAttendees
Property Name: hideAttendees
Property Type: Boolean (default: false)
Property Context: Event, Task
Reference: This document, Section 5.1.3.
Intended Use: Common
Is per-user: no
10.9.12. scheduleSequence
Property Name: scheduleSequence
Property Type: Not applicable
Property Context: Participant
Intended Use: Reserved
Is per-user: no
10.9.13. scheduleUpdated
Property Name: scheduleUpdated
Property Type: Not applicable
Property Context: Participant
Intended Use: Reserved
Is per-user: no
10.9.14. blobId
Property Name: blobId
Property Type: Not applicable
Property Context: Link
Intended Use: Reserved
Is per-user: no
11. 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>.
[RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397,
DOI 10.17487/RFC2397, August 1998,
<https://www.rfc-editor.org/info/rfc2397>.
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[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>.
[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>.
[RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
"DomainKeys Identified Mail (DKIM) Signatures", STD 76,
RFC 6376, DOI 10.17487/RFC6376, September 2011,
<https://www.rfc-editor.org/info/rfc6376>.
[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>.
[RFC8551] Schaad, J., Ramsdell, B., and S. Turner, "Secure/
Multipurpose Internet Mail Extensions (S/MIME) Version 4.0
Message Specification", RFC 8551, DOI 10.17487/RFC8551,
April 2019, <https://www.rfc-editor.org/info/rfc8551>.
[RFC8620] Jenkins, N. and C. Newman, "The JSON Meta Application
Protocol (JMAP)", RFC 8620, DOI 10.17487/RFC8620, July
2019, <https://www.rfc-editor.org/info/rfc8620>.
[RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
"Handling Long Lines in Content of Internet-Drafts and
RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
<https://www.rfc-editor.org/info/rfc8792>.
[RFC8984] Jenkins, N. and R. Stepanek, "JSCalendar: A JSON
Representation of Calendar Data", RFC 8984,
DOI 10.17487/RFC8984, July 2021,
<https://www.rfc-editor.org/info/rfc8984>.
[RFC9562] Davis, K., Peabody, B., and P. Leach, "Universally Unique
IDentifiers (UUIDs)", RFC 9562, DOI 10.17487/RFC9562, May
2024, <https://www.rfc-editor.org/info/rfc9562>.
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[RFC9670] Jenkins, N., Ed., "JSON Meta Application Protocol (JMAP)
Sharing", RFC 9670, DOI 10.17487/RFC9670, November 2024,
<https://www.rfc-editor.org/info/rfc9670>.
[I-D.ietf-calext-jscalendarbis]
Jenkins, N. and R. Stepanek, "JSCalendar: A JSON
Representation of Calendar Data", Work in Progress,
Internet-Draft, draft-ietf-calext-jscalendarbis-10, 16
October 2025, <https://datatracker.ietf.org/doc/html/
draft-ietf-calext-jscalendarbis-10>.
[IANA-TZDB]
IANA, "Time Zone Database",
<https://www.iana.org/time-zones>.
[COLORS] W3C, "CSS Color Module Level 3",
<https://www.w3.org/TR/css-color-3/>.
12. Informative References
[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>.
[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>.
[RFC8607] Daboo, C., Quillaud, A., and K. Murchison, Ed.,
"Calendaring Extensions to WebDAV (CalDAV): Managed
Attachments", RFC 8607, DOI 10.17487/RFC8607, June 2019,
<https://www.rfc-editor.org/info/rfc8607>.
[WCAG] W3C, "Web Content Accessibility Guidelines",
<https://www.w3.org/TR/WCAG21/>.
Authors' Addresses
Neil Jenkins (editor)
Fastmail
PO Box 234, Collins St West
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com
URI: https://www.fastmail.com
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Michael Douglass (editor)
Spherical Cow Group
226 3rd Street
Troy, NY 12180
United States of America
Email: mdouglass@sphericalcowgroup.com
URI: http://sphericalcowgroup.com
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