--- 1/draft-ietf-calext-jscalendar-23.txt 2020-02-19 22:13:23.411653776 -0800
+++ 2/draft-ietf-calext-jscalendar-24.txt 2020-02-19 22:13:23.567657767 -0800
@@ -1,46 +1,46 @@
Calendaring extensions N. Jenkins
Internet-Draft R. Stepanek
Intended status: Standards Track Fastmail
-Expires: August 21, 2020 February 18, 2020
+Expires: August 23, 2020 February 20, 2020
JSCalendar: A JSON representation of calendar data
- draft-ietf-calext-jscalendar-23
+ draft-ietf-calext-jscalendar-24
Abstract
This specification defines a data model and JSON representation of
calendar data that can be used for storage and data exchange in a
- calendaring and scheduling environment. It aims to be an
- alternative, and over time successor to, the widely deployed
- iCalendar data format and to be unambiguous, extendable and simple to
- process. In contrast to the JSON-based jCal format, it is not a
- direct mapping from iCalendar and expands semantics where
- appropriate.
+ calendaring and scheduling environment. It aims to be an alternative
+ and, over time, successor to the widely deployed iCalendar data
+ format, and to be unambiguous, extendable, and simple to process. In
+ contrast to the jCal format, which is also JSON-based, JSCalendar is
+ not a direct mapping from iCalendar, but defines the data model
+ independently and expands semantics where appropriate.
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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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 August 21, 2020.
+ This Internet-Draft will expire on August 23, 2020.
Copyright Notice
Copyright (c) 2020 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
@@ -49,21 +49,21 @@
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Motivation and Relation to iCalendar and jCal . . . . . . 5
1.2. Notational Conventions . . . . . . . . . . . . . . . . . 6
1.3. Type Signatures . . . . . . . . . . . . . . . . . . . . . 6
- 1.4. Data Types . . . . . . . . . . . . . . . . . . . . . . . 6
+ 1.4. Data Types . . . . . . . . . . . . . . . . . . . . . . . 7
1.4.1. Int . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4.2. UnsignedInt . . . . . . . . . . . . . . . . . . . . . 7
1.4.3. UTCDateTime . . . . . . . . . . . . . . . . . . . . . 7
1.4.4. LocalDateTime . . . . . . . . . . . . . . . . . . . . 7
1.4.5. Duration . . . . . . . . . . . . . . . . . . . . . . 7
1.4.6. SignedDuration . . . . . . . . . . . . . . . . . . . 8
1.4.7. Id . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.4.8. PatchObject . . . . . . . . . . . . . . . . . . . . . 9
1.4.9. Time Zones . . . . . . . . . . . . . . . . . . . . . 9
1.4.10. Relation . . . . . . . . . . . . . . . . . . . . . . 9
@@ -88,169 +88,177 @@
4.2.1. title . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2.2. description . . . . . . . . . . . . . . . . . . . . . 15
4.2.3. descriptionContentType . . . . . . . . . . . . . . . 15
4.2.4. showWithoutTime . . . . . . . . . . . . . . . . . . . 15
4.2.5. locations . . . . . . . . . . . . . . . . . . . . . . 15
4.2.6. virtualLocations . . . . . . . . . . . . . . . . . . 17
4.2.7. links . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2.8. locale . . . . . . . . . . . . . . . . . . . . . . . 19
4.2.9. keywords . . . . . . . . . . . . . . . . . . . . . . 19
4.2.10. categories . . . . . . . . . . . . . . . . . . . . . 19
- 4.2.11. color . . . . . . . . . . . . . . . . . . . . . . . . 19
+ 4.2.11. color . . . . . . . . . . . . . . . . . . . . . . . . 20
4.3. Recurrence Properties . . . . . . . . . . . . . . . . . . 20
4.3.1. recurrenceId . . . . . . . . . . . . . . . . . . . . 20
4.3.2. recurrenceRules . . . . . . . . . . . . . . . . . . . 20
4.3.3. recurrenceOverrides . . . . . . . . . . . . . . . . . 28
- 4.3.4. excluded . . . . . . . . . . . . . . . . . . . . . . 29
+ 4.3.4. excluded . . . . . . . . . . . . . . . . . . . . . . 30
4.4. Sharing and Scheduling Properties . . . . . . . . . . . . 30
4.4.1. priority . . . . . . . . . . . . . . . . . . . . . . 30
4.4.2. freeBusyStatus . . . . . . . . . . . . . . . . . . . 30
4.4.3. privacy . . . . . . . . . . . . . . . . . . . . . . . 30
4.4.4. replyTo . . . . . . . . . . . . . . . . . . . . . . . 32
4.4.5. participants . . . . . . . . . . . . . . . . . . . . 32
4.5. Alerts Properties . . . . . . . . . . . . . . . . . . . . 37
4.5.1. useDefaultAlerts . . . . . . . . . . . . . . . . . . 37
4.5.2. alerts . . . . . . . . . . . . . . . . . . . . . . . 37
4.6. Multilingual Properties . . . . . . . . . . . . . . . . . 39
4.6.1. localizations . . . . . . . . . . . . . . . . . . . . 39
4.7. Time Zone Properties . . . . . . . . . . . . . . . . . . 40
4.7.1. timeZone . . . . . . . . . . . . . . . . . . . . . . 40
4.7.2. timeZones . . . . . . . . . . . . . . . . . . . . . . 40
- 5. Type-specific JSCalendar Properties . . . . . . . . . . . . . 42
- 5.1. JSEvent Properties . . . . . . . . . . . . . . . . . . . 42
- 5.1.1. start . . . . . . . . . . . . . . . . . . . . . . . . 42
+ 5. Type-specific JSCalendar Properties . . . . . . . . . . . . . 43
+ 5.1. JSEvent Properties . . . . . . . . . . . . . . . . . . . 43
+ 5.1.1. start . . . . . . . . . . . . . . . . . . . . . . . . 43
5.1.2. duration . . . . . . . . . . . . . . . . . . . . . . 43
5.1.3. status . . . . . . . . . . . . . . . . . . . . . . . 43
- 5.2. JSTask Properties . . . . . . . . . . . . . . . . . . . . 43
- 5.2.1. due . . . . . . . . . . . . . . . . . . . . . . . . . 43
+ 5.2. JSTask Properties . . . . . . . . . . . . . . . . . . . . 44
+ 5.2.1. due . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.2.2. start . . . . . . . . . . . . . . . . . . . . . . . . 44
5.2.3. estimatedDuration . . . . . . . . . . . . . . . . . . 44
5.2.4. progress . . . . . . . . . . . . . . . . . . . . . . 44
5.2.5. progressUpdated . . . . . . . . . . . . . . . . . . . 45
5.3. JSGroup Properties . . . . . . . . . . . . . . . . . . . 45
5.3.1. entries . . . . . . . . . . . . . . . . . . . . . . . 46
5.3.2. source . . . . . . . . . . . . . . . . . . . . . . . 46
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.1. Simple event . . . . . . . . . . . . . . . . . . . . . . 46
- 6.2. Simple task . . . . . . . . . . . . . . . . . . . . . . . 46
+ 6.2. Simple task . . . . . . . . . . . . . . . . . . . . . . . 47
6.3. Simple group . . . . . . . . . . . . . . . . . . . . . . 47
- 6.4. All-day event . . . . . . . . . . . . . . . . . . . . . . 47
+ 6.4. All-day event . . . . . . . . . . . . . . . . . . . . . . 48
6.5. Task with a due date . . . . . . . . . . . . . . . . . . 48
- 6.6. Event with end time-zone . . . . . . . . . . . . . . . . 48
+ 6.6. Event with end time-zone . . . . . . . . . . . . . . . . 49
6.7. Floating-time event (with recurrence) . . . . . . . . . . 49
- 6.8. Event with multiple locations and localization . . . . . 49
- 6.9. Recurring event with overrides . . . . . . . . . . . . . 50
- 6.10. Recurring event with participants . . . . . . . . . . . . 51
- 7. Security Considerations . . . . . . . . . . . . . . . . . . . 53
- 7.1. Expanding Recurrences . . . . . . . . . . . . . . . . . . 53
- 7.2. JSON Parsing . . . . . . . . . . . . . . . . . . . . . . 53
- 7.3. URI Values . . . . . . . . . . . . . . . . . . . . . . . 54
- 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 54
- 8.1. Media Type Registration . . . . . . . . . . . . . . . . . 54
- 8.2. Creation of "JSCalendar Properties" Registry . . . . . . 55
- 8.2.1. Preliminary Community Review . . . . . . . . . . . . 56
- 8.2.2. Submit Request to IANA . . . . . . . . . . . . . . . 56
- 8.2.3. Designated Expert Review . . . . . . . . . . . . . . 56
- 8.2.4. Change Procedures . . . . . . . . . . . . . . . . . . 57
- 8.2.5. JMAP Properties Registry Template . . . . . . . . . . 57
+ 6.8. Event with multiple locations and localization . . . . . 50
+ 6.9. Recurring event with overrides . . . . . . . . . . . . . 51
+ 6.10. Recurring event with participants . . . . . . . . . . . . 52
+ 7. Security Considerations . . . . . . . . . . . . . . . . . . . 54
+ 7.1. Expanding Recurrences . . . . . . . . . . . . . . . . . . 54
+ 7.2. JSON Parsing . . . . . . . . . . . . . . . . . . . . . . 54
+ 7.3. URI Values . . . . . . . . . . . . . . . . . . . . . . . 55
+ 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 55
+ 8.1. Media Type Registration . . . . . . . . . . . . . . . . . 55
+ 8.2. Creation of "JSCalendar Properties" Registry . . . . . . 56
+ 8.2.1. Preliminary Community Review . . . . . . . . . . . . 57
+ 8.2.2. Submit Request to IANA . . . . . . . . . . . . . . . 57
+ 8.2.3. Designated Expert Review . . . . . . . . . . . . . . 57
+ 8.2.4. Change Procedures . . . . . . . . . . . . . . . . . . 58
+ 8.2.5. JMAP Properties Registry Template . . . . . . . . . . 58
8.2.6. Initial Contents for the JSCalendar Properties
- Registry . . . . . . . . . . . . . . . . . . . . . . 58
- 8.3. Creation of "JSCalendar Types" Registry . . . . . . . . . 65
- 8.3.1. JMAP Types Registry Template . . . . . . . . . . . . 65
- 8.3.2. Initial Contents for the JSCalendar Types Registry . 65
- 8.4. Creation of "JSCalendar Enum Values" Registry . . . . . . 67
- 8.4.1. JMAP Enum Subregistry Creation Template . . . . . . . 67
- 8.4.2. JMAP Enum Subregistry Template . . . . . . . . . . . 67
- 8.4.3. Initial Contents for the JSCalendar Enum Registry . . 68
- 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 72
- 10. Informative References . . . . . . . . . . . . . . . . . . . 72
- Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 75
+ Registry . . . . . . . . . . . . . . . . . . . . . . 59
+ 8.3. Creation of "JSCalendar Types" Registry . . . . . . . . . 66
+ 8.3.1. JMAP Types Registry Template . . . . . . . . . . . . 66
+ 8.3.2. Initial Contents for the JSCalendar Types Registry . 66
+ 8.4. Creation of "JSCalendar Enum Values" Registry . . . . . . 68
+ 8.4.1. JMAP Enum Subregistry Creation Template . . . . . . . 68
+ 8.4.2. JMAP Enum Subregistry Template . . . . . . . . . . . 68
+ 8.4.3. Initial Contents for the JSCalendar Enum Registry . . 69
+ 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 73
+ 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 73
+ 10.1. Normative References . . . . . . . . . . . . . . . . . . 73
+ 10.2. Informative References . . . . . . . . . . . . . . . . . 75
+ Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 76
1. Introduction
This document defines a data model for calendar event and task
objects, or groups of such objects, in electronic calendar
applications and systems. It aims to be unambiguous, extendable and
simple to process.
The key design considerations for this data model are as follows:
o The attributes of the calendar entry represented must be described
- as a simple key-value pair. Simple events are simple to
- represent, complex events can be modelled accurately.
+ as simple key-value pairs. Simple events are simple to represent;
+ complex events can be modelled accurately.
o Wherever possible, there should be only one way to express the
desired semantics, reducing complexity.
- o The data model should avoid ambiguities and make it difficult to
- make mistakes during implementation.
+ o The data model should avoid ambiguities, which often lead to
+ interoperability issues between implementations.
o The data model should be compatible with the iCalendar data format
[RFC5545] [RFC7986] and extensions, but the specification should
add new attributes where the iCalendar format currently lacks
- expressivity, and drop widely unused, obsolete or redundant
+ expressivity, and drop seldom-used, obsolete, or redundant
properties. This means translation with no loss of semantics
- should be easy with most common iCalendar files but is not
- guaranteed with the full specification.
+ should be easy with most common iCalendar files.
- o Extensions, such as new properties and components, MUST NOT lead
- to requiring an update to this document.
+ o Extensions, such as new properties and components, generally do
+ not require updates to this document.
The representation of this data model is defined in the I-JSON format
[RFC7493], which is a strict subset of the JavaScript Object Notation
(JSON) Data Interchange Format [RFC8259]. Using JSON is mostly a
pragmatic choice: its widespread use makes JSCalendar easier to
adopt, and the ready availability of production-ready JSON
implementations eliminates a whole category of parser-related
interoperability issues, which iCalendar has often suffered from.
1.1. Motivation and Relation to iCalendar and jCal
The iCalendar data format [RFC5545], a widely deployed interchange
format for calendaring and scheduling data, has served calendaring
vendors for a long while, but contains some ambiguities and pitfalls
that can not be overcome without backward-incompatible changes.
- For example, iCalendar defines various formats for local times, UTC
- time and dates, which confuses new users and often leads to
- implementation errors. Other sources for errors are the requirement
- for custom time zone definitions within a single calendar component,
- as well as the iCalendar format itself; the latter causing
- interoperability issues due to misuse of CR LF terminated strings,
- line continuations and subtle differences between iCalendar parsers.
- The definition of recurrence rules is ambiguous and has resulted in
- differing understandings even between experienced calendar
- developers.
+ Sources of implementation errors include the following:
+
+ o iCalendar defines various formats for local times, UTC time, and
+ dates.
+
+ o iCalendar requires custom time zone definitions within a single
+ calendar component.
+
+ o iCalendar's definition of recurrence rules is ambiguous and has
+ resulted in differing understandings even between experienced
+ calendar developers.
+
+ o The iCalendar format itself causes interoperability issues due to
+ misuse of CRLF-terminated strings, line continuations, and subtle
+ differences among iCalendar parsers.
In recent years, many new products and services have appeared that
- wish to use a JSON representation of calendar data within their API.
+ wish to use a JSON representation of calendar data within their APIs.
The JSON format for iCalendar data, jCal [RFC7265], is a direct
mapping between iCalendar and JSON. In its effort to represent full
iCalendar semantics, it inherits all the same pitfalls and uses a
complicated JSON structure unlike most common JSON data
representations.
As a consequence, since the standardization of jCal, the majority of
implementations and service providers either kept using iCalendar, or
came up with their own proprietary JSON representations, which are
incompatible with each other and often suffer from common pitfalls,
such as storing event start times in UTC (which become incorrect if
- the timezone's rules change in the future). JSCalendar is intended
- to meet this demand for JSON-formatted calendar data, and to provide
- a standard, elegant representation as an alternative to new
- proprietary formats.
+ the timezone's rules change in the future). JSCalendar meets the
+ demand for JSON-formatted calendar data that is free of such known
+ problems and provides a standard representation as an alternative to
+ the proprietary formats.
1.2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
- "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
- document are to be interpreted as described in [RFC2119].
+ "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.
The underlying format used for this specification is JSON.
Consequently, the terms "object" and "array" as well as the four
primitive types (strings, numbers, booleans, and null) are to be
interpreted as described in Section 1 of [RFC8259].
Some examples in this document contain "partial" JSON documents used
for illustrative purposes. In these examples, three periods "..."
are used to indicate a portion of the document that has been removed
for compactness.
@@ -269,64 +277,62 @@
o "Boolean" - The JSON boolean type.
o "A[B]" - A JSON object where the keys are all of type "A", and the
values are all of type "B".
o "A[]" - An array of values of type "A".
o "A|B" - The value is either of type "A" or of type "B".
- Other types may also be given, with their representation defined
+ Other types may also be given, with their representations defined
elsewhere in this document.
1.4. Data Types
In addition to the standard JSON data types, the following data types
are used in this specification:
1.4.1. Int
Where "Int" is given as a data type, it means an integer in the range
-2^53+1 <= value <= 2^53-1, the safe range for integers stored in a
floating-point double, represented as a JSON "Number".
1.4.2. UnsignedInt
- Where "UnsignedInt" is given as a data type, it means an "Int" where
- the value MUST be in the range 0 <= value <= 2^53-1.
+ Where "UnsignedInt" is given as a data type, it means an integer in
+ the range 0 <= value <= 2^53-1, represented as a JSON "Number".
1.4.3. UTCDateTime
This is a string in [RFC3339] "date-time" format, with the further
restrictions that any letters MUST be in uppercase, the time
component MUST be included and the time offset MUST be the character
"Z". Fractional second values MUST NOT be included unless non-zero
and MUST NOT have trailing zeros, to ensure there is only a single
representation for each date-time.
For example "2010-10-10T10:10:10.003Z" is OK, but
"2010-10-10T10:10:10.000Z" is invalid and MUST be encoded as
"2010-10-10T10:10:10Z".
- In common notation, it should be of the form "YYYY-MM-DDTHH:MM:SSZ".
-
1.4.4. LocalDateTime
This is a date-time string with no time zone/offset information. It
is otherwise in the same format as UTCDateTime, including fractional
seconds. For example "2006-01-02T15:04:05" and
"2006-01-02T15:04:05.003" are both valid. The time zone to associate
the LocalDateTime with comes from an associated property, or if no
time zone is associated it defines *floating time*. Floating date-
times are not tied to any specific time zone. Instead, they occur in
- every time zone at the same wall-clock time (as opposed to the same
+ each time zone at the given wall-clock time (as opposed to the same
instant point in time).
1.4.5. Duration
Where Duration is given as a type, it means a length of time
represented by a subset of ISO8601 duration format, as specified by
the following ABNF:
dur-secfrac = "." 1*DIGIT
dur-second = 1*DIGIT [dur-secfrac] "S"
@@ -342,160 +348,155 @@
unless the fraction is non-zero.
1.4.6. SignedDuration
A SignedDuration represents a length of time that may be positive or
negative and is typically used to express the offset of a point in
time relative to an associated time. It is represented as a
Duration, optionally preceded by a sign character. It is specified
by the following ABNF:
- signed-duration = (["+"] / "-") duration
+ signed-duration = ["+" / "-"] duration
A negative sign indicates a point in time at or before the associated
time, a positive or no sign a time at or after the associated time.
1.4.7. Id
Where "Id" is given as a data type, it means a "String" of at least 1
and a maximum of 255 octets in size, and it MUST only contain
- characters from the "URL and Filename Safe" base64 alphabet, as
+ characters from the "URL and Filename Safe" base64url alphabet, as
defined in Section 5 of [RFC4648], excluding the pad character ("=").
This means the allowed characters are the ASCII alphanumeric
characters ("A-Za-z0-9"), hyphen ("-"), and underscore ("_").
Unless otherwise specified, Ids are arbitrary and only have meaning
within the object where they are being used. Ids need not be unique
- between different objects. For example, two JSEvent objects MAY use
+ among different objects. For example, two JSEvent objects might use
the same ids in their respective "links" properties. Or within the
same JSEvent object the same Id could appear in the "participants"
- and "alerts" properties. This does not imply any semantic connection
- between the two.
+ and "alerts" properties. These situations do not imply any semantic
+ connections among the objects.
Nevertheless, a UUID is typically a good choice.
1.4.8. PatchObject
A PatchObject is of type "String[*]", and represents an unordered set
- of patches on a JSON object. The keys are a path in a subset of
- [RFC6901] JSON pointer format, with an implicit leading "/" (i.e.
- prefix each key with "/" before applying the JSON pointer evaluation
- algorithm).
+ of patches on a JSON object. Each key is a path represented in a
+ subset of JSON pointer format [RFC6901]. The paths have an implicit
+ leading "/", so each key is prefixed with "/" before applying the
+ JSON pointer evaluation algorithm.
A patch within a PatchObject is only valid if all of the following
conditions apply:
- 1. The pointer MUST NOT reference inside an array (i.e. it MUST NOT
- insert/delete from an array; the array MUST be replaced in its
- entirety instead).
+ 1. The pointer MUST NOT insert/delete from an array; the array MUST
+ be replaced in its entirety instead.
- 2. When evaluating a path, all parts prior to the last (i.e. the
+ 2. When evaluating a path, all parts prior to the last (i.e., the
value after the final slash) MUST exist.
3. There MUST NOT be two patches in the PatchObject where the
- pointer of one is the prefix of the pointer of the other, e.g.
+ pointer of one is a prefix of the pointer of the other, e.g.,
"alerts/foo/offset" and "alerts".
The value associated with each pointer is either:
- o null: Remove the property from the patched object. If not present
- in the parent, this a no-op.
+ o null: Remove the property at the given path from the patched
+ object. If the property is not present in the object, this a no-
+ op.
- o Anything else: The value to set for this property (this may be a
- replacement or addition to the object being patched).
+ o Anything else: Set the value for the property to this value (this
+ may be a replacement or addition to the object being patched).
- Implementations MUST reject a PatchObject if any of its patches are
- invalid.
+ Implementations MUST reject in its entirety a PatchObject if any of
+ its patches is invalid. Implementations MUST NOT apply partial
+ patches.
1.4.9. Time Zones
- By default, time zones in JSCalendar are identified by their name in
+ By default, time zones in JSCalendar are identified by their names in
the IANA Time Zone Database [TZDB], and the zone rules of the
- respective zone record apply.
+ respective zone records apply.
- Implementations MAY embed the definition of custom time zones in the
+ Implementations MAY embed the definitions of custom time zones in the
"timeZones" property (see Section 4.7.2).
1.4.10. Relation
A Relation object defines the relation to other objects, using a
possibly empty set of relation types. The object that defines this
- relation is the linking object, the other object is the linked
- object. The Relation object has the following property:
+ relation is the linking object, while the other object is the linked
+ object. The Relation object has the following properties:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Relation".
o relation: "String[Boolean]" (optional, default: empty Object)
Describes how the linked object is related to the linking object.
The relation is defined as a set of relation types. If empty, the
relationship between the two objects is unspecified.
Keys in the set MUST be one of the following values, or specified
- in the property definition where the Relation object is used, or
- an IANA-registered value, or a vendor-specific value:
+ in the property definition where the Relation object is used, or a
+ value registered in the IANA JSCalendar Enum Registry, or a
+ vendor-specific value:
* "first": The linked object is the first in a series the linking
object is part of.
* "next": The linked object is the next in a series the linking
object is part of.
* "child": The linked object is a subpart of the linking object.
- * "parent": The linking object is part of the overall linked
- object.
+ * "parent": The linking object is a subpart of the linked object.
The value for each key in the set MUST be true.
- Note, the Relation object only has one property (except @type); it is
- specified as an object with a single property to allow for extension
- in the future.
-
2. JSCalendar Objects
This section describes the calendar object types specified by
JSCalendar.
2.1. JSEvent
- MIME type: "application/jscalendar+json;type=jsevent"
+ Media type: "application/jscalendar+json;type=jsevent"
A JSEvent represents a scheduled amount of time on a calendar,
- typically a meeting, appointment, reminder or anniversary. Multiple
- participants may partake in the event at multiple locations.
+ typically a meeting, appointment, reminder or anniversary. It is
+ required to start at a certain point in time and typically has a non-
+ zero duration. Multiple participants may partake in the event at
+ multiple locations.
The @type (Section 4.1.1) property value MUST be "jsevent".
2.2. JSTask
- MIME type: "application/jscalendar+json;type=jstask"
+ Media type: "application/jscalendar+json;type=jstask"
A JSTask represents an action-item, assignment, to-do or work item.
+ It may start and be due at certain points in time, may take some
+ estimated time to complete, and may recur, none of which is required.
The @type (Section 4.1.1) property value MUST be "jstask".
- A JSTask may start and be due at certain points in time, may take
- some estimated time to complete and may recur; none of which is
- required. This notably differs from JSEvent (Section 2.1) which is
- required to start at a certain point in time and typically takes some
- non-zero duration to complete.
-
2.3. JSGroup
- MIME type: "application/jscalendar+json;type=jsgroup"
+ Media type: "application/jscalendar+json;type=jsgroup"
A JSGroup is a collection of JSEvent (Section 2.1) and/or JSTask
- (Section 2.2) objects. Typically, objects are grouped by topic (e.g.
- by keywords) or calendar membership.
+ (Section 2.2) objects. Typically, objects are grouped by topic
+ (e.g., by keywords) or calendar membership.
The @type (Section 4.1.1) property value MUST be "jsgroup".
3. Structure of JSCalendar Objects
A JSCalendar object is a JSON object, which MUST be valid I-JSON (a
stricter subset of JSON), as specified in [RFC8259]. Property names
and values are case-sensitive.
The object has a collection of properties, as specified in the
@@ -514,77 +515,77 @@
the encoded calendar object to determine ETag equivalence).
Normalization of JSCalendar objects is hindered because of the
following reasons:
o Custom JSCalendar properties may contain arbitrary JSON values,
including arrays. However, equivalence of arrays might or might
not depend on the order of elements, depending on the respective
property definition.
- o Several JSCalendar property values are defined as URIs and MIME
- types, but normalization of these types is inherently protocol and
- scheme-specific, depending on the use-case of the equivalence
+ o Several JSCalendar property values are defined as URIs and media
+ types, but normalization of these types is inherently protocol-
+ and scheme-specific, depending on the use-case of the equivalence
definition (see Section 6 of [RFC3986]).
Considering this, the definition of equivalence and normalization is
left to client and server implementations and to be negotiated by a
- calendar exchange protocol or defined by another RFC.
+ calendar exchange protocol or defined elsewhere.
3.2. Vendor-specific Property Extensions and Values
Vendors MAY add additional properties to the calendar object to
support their custom features. The names of these properties MUST be
prefixed with a domain name controlled by the vendor to avoid
- conflict, e.g. "example.com/customprop".
+ conflict, e.g., "example.com/customprop".
Some JSCalendar properties allow vendor-specific value extensions.
- If so, vendor-specific values MUST be prefixed with a domain name
- controlled by the vendor, e.g. "example.com/customrel".
+ Such vendor-specific values MUST be prefixed with a domain name
+ controlled by the vendor, e.g., "example.com/customrel".
Vendors are strongly encouraged to register any new property values
or extensions that are useful to other systems as well, rather than
use a vendor-specific prefix.
4. Common JSCalendar Properties
This section describes the properties that are common to the various
JSCalendar object types. Specific JSCalendar object types may only
support a subset of these properties. The object type definitions in
Section 5 describe the set of supported properties per type.
4.1. Metadata Properties
4.1.1. @type
Type: "String" (mandatory).
Specifies the type which this object represents. This MUST be one of
- the following values, an IANA-registered value, or a vendor-specific
- value:
+ the following values:
o "jsevent": a JSCalendar event (Section 2.1).
o "jstask": a JSCalendar task (Section 2.2).
o "jsgroup": a JSCalendar group (Section 2.3).
4.1.2. uid
Type: "String" (mandatory).
A globally unique identifier, used to associate the object as the
same across different systems, calendars and views. The value of
this property MUST be unique across all JSCalendar objects, even if
they are of different type. [RFC4122] describes a range of
established algorithms to generate universally unique identifiers
- (UUID), and the random or pseudo-random version is recommended.
+ (UUID). UUID version 4, described in Section 4.4 of [RFC4122], is
+ RECOMMENDED.
For compatibility with [RFC5545] UIDs, implementations MUST be able
to receive and persist values of at least 255 octets for this
property, but they MUST NOT truncate values in the middle of a UTF-8
multi-octet sequence.
4.1.3. relatedTo
Type: "String[Relation]" (optional).
@@ -611,33 +612,35 @@
modified (i.e., whenever the "updated" property is set).
The vendor of the implementation SHOULD ensure that this is a
globally unique identifier, using some technique such as an FPI
value, as defined in [ISO.9070.1991]. It MUST only use characters of
an iCalendar TEXT data value (see Section 3.3.11 of [RFC5545]).
This property SHOULD NOT be used to alter the interpretation of a
JSCalendar object beyond the semantics specified in this document.
For example, it is not to be used to further the understanding of
- non-standard properties.
+ non-standard properties, a practice that is knows to cause long-term
+ interoperability problems.
4.1.5. created
Type: "UTCDateTime" (optional).
The date and time this object was initially created.
4.1.6. updated
Type: "UTCDateTime" (mandatory).
- The date and time the data in this object was last modified.
+ The date and time the data in this object was last modified (or its
+ creation date/time if not modified since).
4.1.7. sequence
Type: "UnsignedInt" (optional, default: 0).
Initially zero, this MUST be incremented by one every time a change
is made to the object, except if the change only modifies the
"participants" property (see Section 4.4.5).
This is used as part of iTIP [RFC5546] to know which version of the
@@ -665,31 +668,31 @@
A longer-form text description of the object. The content is
formatted according to the "descriptionContentType" property.
4.2.3. descriptionContentType
Type: "String" (optional, default: "text/plain").
Describes the media type [RFC6838] of the contents of the
"description" property. Media types MUST be sub-types of type
"text", and SHOULD be "text/plain" or "text/html" [MIME]. They MAY
- define parameters and the "charset" parameter value MUST be "utf-8",
+ include parameters and the "charset" parameter value MUST be "utf-8",
if specified. Descriptions of type "text/html" MAY contain "cid"
URLs [RFC2392] to reference links in the calendar object by use of
the "cid" property of the Link object.
4.2.4. showWithoutTime
Type: "Boolean" (optional, default: false).
- Indicates the time is not important to display to the user when
- rendering this calendar object, for example an event that
+ Indicates that the time is not important to display to the user when
+ rendering this calendar object. An example of this is an event that
conceptually occurs all day or across multiple days, such as "New
Year's Day" or "Italy Vacation". While the time component is
important for free-busy calculations and checking for scheduling
clashes, calendars may choose to omit displaying it and/or display
the object separately to other objects to enhance the user's view of
their schedule.
Such events are also commonly known as "all-day" events.
4.2.5. locations
@@ -719,46 +722,53 @@
o locationTypes: "String[Boolean]" (optional)
A set of one or more location types that describe this location.
All types MUST be from the Location Types Registry as defined in
[RFC4589]. The set is represented as a map, with the keys being
the location types. The value for each key in the map MUST be
true.
o relativeTo: "String" (optional)
- The relation type of this location to the JSCalendar object.
+ Specifies the relation between this location and the time of the
+ JSCalendar object. This is primarily to allow events representing
+ travel to specify the location of departure (at the start of the
+ event) and location of arrival (at the end); this is particularly
+ important if these locations are in different time zones, as a
+ client may wish to highlight this information for the user.
- This MUST be either one of the following values, an IANA-
- registered value, or a vendor-specific value. Any value the
- client or server doesn't understand should be treated the same as
- if this property is omitted.
+ This MUST be one of the following values, a value registered in
+ the IANA JSCalendar Enum Registry, or a vendor-specific value.
+ Any value the client or server doesn't understand should be
+ treated the same as if this property is omitted.
- * "start": The JSCalendar object starts at this location.
+ * "start": The event/task described by this JSCalendar object
+ occurs at this location at the time the event/task starts.
- * "end": The JSCalendar object ends at this location.
+ * "end": The event/task described by this JSCalendar object
+ occurs at this location at the time the event/task ends.
o timeZone: "String" (optional)
A time zone for this location. See also Section 1.4.9.
o coordinates: "String" (optional)
A "geo:" URI [RFC5870] for the location.
o linkIds: "Id[Boolean]" (optional)
-
- A set of link ids for links to alternate representations of this
+ A set of link ids for links to alternative representations of this
location. Each key in the set MUST be the id of a Link object
defined in the "links" property of this calendar object. The
- value for each key in the set MUST be true. This MUST be omitted
- if none (rather than an empty set).
+ value for each key in the set MUST be true. If there are no
+ links, this MUST be omitted (rather than specified as an empty
+ set).
For example, an alternative representation could be in vCard
format.
4.2.6. virtualLocations
Type: "Id[VirtualLocation]" (optional).
A map of ids to VirtualLocation objects, representing virtual
locations, such as video conferences or chat rooms, associated with
@@ -799,65 +809,66 @@
A Link object has the following properties:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Link".
o href: "String" (mandatory)
A URI from which the resource may be fetched.
- This MAY be a "data:" URL, but it is recommended that the file be
- hosted on a server to avoid embedding arbitrarily large data in
- JSCalendar object instances.
+ This MAY be a "data:" URL [RFC2397], but it is recommended that
+ the file be hosted on a server to avoid embedding arbitrarily
+ large data in JSCalendar object instances.
o cid: "String" (optional)
This MUST be a valid "content-id" value according to the
definition of Section 2 in [RFC2392]. The value MUST be unique
within this Link object but has no meaning beyond that. It MAY be
different from the link id for this Link object.
o contentType: "String" (optional)
- The content-type [RFC6838] of the resource, if known.
+ The media type [RFC6838] of the resource, if known.
o size: "UnsignedInt" (optional)
- The size, in octets, of the resource when fully decoded (i.e. the
+ The size, in octets, of the resource when fully decoded (i.e., the
number of octets in the file the user would download), if known.
o rel: "String" (optional)
Identifies the relation of the linked resource to the object. If
set, the value MUST be a relation type from the IANA registry
[LINKRELS], as established in [RFC8288].
Links with a rel of "enclosure" SHOULD be considered by the client
as attachments for download.
Links with a rel of "describedby" SHOULD be considered by the
- client to be an alternate representation of the description.
+ client to be an alternative representation of the description.
Links with a rel of "icon" SHOULD be considered by the client to
- be an image that it MAY use when presenting the calendar data to a
- user. The "display" property MAY be set to indicate the purpose
+ be an image that it may use when presenting the calendar data to a
+ user. The "display" property may be set to indicate the purpose
of this image.
o display: "String" (optional)
Describes the intended purpose of a link to an image. If set, the
- "rel" property MUST be set to "icon". The value MUST be either
- one of the following values, an IANA-registered value, or a
- vendor-specific value:
+ "rel" property MUST be set to "icon". The value MUST be one of
+ the following values, a value registered in the IANA JSCalendar
+ Enum Registry, or a vendor-specific value:
- * "badge": an image inline with the title of the object.
+ * "badge": an image meant to be displayed alongside the title of
+ the object.
* "graphic": a full image replacement for the object itself.
* "fullsize": an image that is used to enhance the object.
* "thumbnail": a smaller variant of "fullsize" to be used when
space for the image is constrained.
o title: "String" (optional)
@@ -889,32 +900,31 @@
In contrast to keywords, categories typically are structured. For
example, a vendor owning the domain "example.com" might define the
categories "http://example.com/categories/sports/american-football""
and "http://example.com/categories/music/r-b".
4.2.11. color
Type: "String" (optional).
A color clients MAY use when displaying this calendar object. The
- value is 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.
+ value is a 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.
4.3. Recurrence Properties
- Some events and tasks occur at regular, or indeed irregular,
- intervals. Rather than having to copy the data for every occurrence,
- you can instead have a master event with a recurrence rule generating
- the occurrences, and/or overrides that add extra dates or exceptions
- to the rule.
+ Some events and tasks occur at regular or irregular intervals.
+ Rather than having to copy the data for every occurrence there can be
+ a master event with a recurrence rule, and/or overrides that add
+ extra dates or exceptions to the rule.
4.3.1. recurrenceId
Type: "LocalDateTime" (optional).
If present, this JSCalendar object represents one occurrence of a
recurring JSCalendar object. If present the "recurrenceRules" and
"recurrenceOverrides" properties MUST NOT be present.
The value is a date-time either produced by the "recurrenceRules" of
@@ -927,21 +937,21 @@
Defines a set of recurrence rules (repeating patterns) for recurring
calendar objects.
A JSEvent recurs by applying the recurrence rules to the "start"
date-time.
A JSTask recurs by applying the recurrence rules to the "start" date-
time, if defined, otherwise it recurs by the "due" date-time, if
defined. If the task defines neither a "start" nor "due" date-time,
- its "recurrenceRules" property value MUST be null.
+ it MUST NOT define a "recurrenceRules" property.
If multiple recurrence rules are given, each rule is to be applied
and then the union of the results used, ignoring any duplicates.
A RecurrenceRule object is a JSON object mapping of a RECUR value
type in iCalendar [RFC5545] [RFC7529] and has the same semantics. It
has the following properties:
o @type: "String" (mandatory)
@@ -973,22 +983,21 @@
The interval of iteration periods at which the recurrence repeats.
If included, it MUST be an integer >= 1.
This is the INTERVAL part from iCalendar.
o rscale: "String" (optional, default: "gregorian")
The calendar system in which this recurrence rule operates, in
lowercase. This MUST be either a CLDR-registered calendar system
- name, or a non-standard, experimental calendar system name
- prefixed with the characters "x-".
+ name [CLDR], or a vendor-specific value.
This is the RSCALE part from iCalendar RSCALE [RFC7529], converted
to lowercase.
o skip: "String" (optional, default: "omit")
The behaviour to use when the expansion of the recurrence produces
invalid dates. This property only has an effect if the frequency
is "yearly" or "monthly". It MUST be one of the following values:
@@ -1036,41 +1046,41 @@
converted to lowercase.
* nthOfPeriod: "Int" (optional)
If present, rather than representing every occurrence of the
weekday defined in the "day" property, it represents only a
specific instance within the recurrence period. The value can
be positive or negative, but MUST NOT be zero. A negative
integer means nth-last of period.
- This is the ordinal part of the BYDAY value in iCalendar (e.g.
+ This is the ordinal part of the BYDAY value in iCalendar (e.g.,
1 or -3).
o byMonthDay: "Int[]" (optional)
Days of the month on which to repeat. Valid values are between 1
and the maximum number of days any month may have in the calendar
given by the "rscale" property, and the negative values of these
numbers. For example, in the Gregorian calendar valid values are
1 to 31 and -31 to -1. Negative values offset from the end of the
month. The array MUST have at least one entry if included.
This is the BYMONTHDAY part in iCalendar.
o byMonth: "String[]" (optional)
The months in which to repeat. Each entry is a string
representation of a number, starting from "1" for the first month
- in the calendar (e.g. "1" means January with the Gregorian
+ in the calendar (e.g., "1" means January with the Gregorian
calendar), with an optional "L" suffix (see [RFC7529]) for leap
- months (this MUST be uppercase, e.g. "3L"). The array MUST have
+ months (this MUST be uppercase, e.g., "3L"). The array MUST have
at least one entry if included.
This is the BYMONTH part from iCalendar.
o byYearDay: "Int[]" (optional)
The days of the year on which to repeat. Valid values are between
1 and the maximum number of days any year may have in the calendar
given by the "rscale" property, and the negative values of these
numbers. For example, in the Gregorian calendar valid values are
@@ -1219,53 +1229,53 @@
year (if frequency is yearly). Negative numbers means nth
last occurrence within that period.
* byHour: the date-time has the given hour value.
* byMinute: the date-time has the given minute value.
* bySecond: the date-time has the given second value.
If a skip property is defined and is not "omit", there may be
- candidates that do not correspond to valid dates (e.g. 31st
+ candidates that do not correspond to valid dates (e.g., 31st
February in the Gregorian calendar). In this case, the
properties MUST be considered in the order above and:
1. After applying the byMonth filter, if the candidate's month
- is invalid for the given year increment it (if skip is
+ is invalid for the given year, increment it (if skip is
"forward") or decrement it (if skip is "backward") until a
valid month is found, incrementing/decrementing the year as
- well if you pass through the beginning/end of the year. This
+ well if passing through the beginning/end of the year. This
only applies to calendar systems with leap months.
2. After applying the byMonthDay filter, if the day of the month
is invalid for the given month and year, change the date to
- the first day of the next month (if skip == "forward") or the
- last day of the current month (if skip == "backward").
+ the first day of the next month (if skip is "forward") or the
+ last day of the current month (if skip is "backward").
3. If any valid date produced after applying the skip is already
a candidate, eliminate the duplicate. (For example after
adjusting, 30th February and 31st February would both become
the same "real" date, so one is eliminated as a duplicate.)
3. If a bySetPosition property is included, this is now applied to
the ordered list of remaining dates. This property specifies the
indexes of date-times to keep; all others should be eliminated.
Negative numbers are indexes from the end of the list, with -1
being the last item.
4. Any date-times before the start date of the event are eliminated
(see below for why this might be needed).
5. If a skip property is included and is not "omit", eliminate any
date-times that have already been produced by previous iterations
- of the algorithm. (This is not possible if skip == "omit".)
+ of the algorithm. (This is not possible if skip is "omit".)
6. If further dates are required (we have not reached the until
date, or count limit) skip the next (interval - 1) sets of
candidates, then continue from step 1.
When determining the set of occurrence dates for an event or task,
the following extra rules must be applied:
1. The initial date-time to which the rule is applied (the "start"
date-time for events; the "start" or "due" date-time for tasks)
@@ -1390,23 +1400,24 @@
The priority is specified as an integer in the range 0 to 9. A value
of 0 specifies an undefined priority. A value of 1 is the highest
priority. A value of 2 is the second highest priority. Subsequent
numbers specify a decreasing ordinal priority. A value of 9 is the
lowest priority. Other integer values are reserved for future use.
4.4.2. freeBusyStatus
Type: "String" (optional, default: "busy").
- Specifies how this property should be treated when calculating free-
- busy state. This MUST be one of the following values, an IANA-
- registered value, or a vendor-specific value:
+ Specifies how this calendar object should be treated when calculating
+ free-busy state. This MUST be one of the following values, a value
+ registered in the IANA JSCalendar Enum Registry, or a vendor-specific
+ value:
o "free": The object should be ignored when calculating whether the
user is busy.
o "busy": The object should be included when calculating whether the
user is busy.
4.4.3. privacy
Type: "String" (optional, default: "public").
@@ -1415,24 +1426,24 @@
with other users. The privacy property allows the object owner to
indicate that it should not be shared, or should only have the time
information shared but the details withheld. Enforcement of the
restrictions indicated by this property are up to the API via which
this object is accessed.
This property MUST NOT affect the information sent to scheduled
participants; it is only interpreted when the object is shared as
part of a shared calendar.
- The value MUST be either one of the following values, an IANA-
- registered value, or a vendor-specific value. Any value the client
- or server doesn't understand should be preserved but treated as
- equivalent to "private".
+ The value MUST be one of the following values, a value registered in
+ the IANA JSCalendar Enum Registry, or a vendor-specific value. Any
+ value the client or server doesn't understand should be preserved but
+ treated as equivalent to "private".
o "public": The full details of the object are visible to those whom
the object's calendar is shared with.
o "private": The details of the object are hidden; only the basic
time and metadata is shared. The following properties MAY be
shared, any other properties MUST NOT be shared:
* @type
@@ -1468,38 +1478,39 @@
o "secret": The object is hidden completely (as though it did not
exist) when the calendar this object is in is shared.
4.4.4. replyTo
Type: "String[String]" (optional).
Represents methods by which participants may submit their RSVP
response to the organizer of the calendar object. The keys in the
property value are the available methods and MUST only contain ASCII
- alphanumeric characters (A-Za-z0-9). The value is a URI to use that
- method. Future methods may be defined in future specifications and
- registered with IANA; a calendar client MUST ignore any method it
- does not understand, but MUST preserve the method key and URI. This
- property MUST be omitted if no method is defined (rather than an
- empty object). If this property is set, the "participants" property
- of this calendar object MUST contain at least one participant.
+ alphanumeric characters (A-Za-z0-9). The value is a URI for the
+ method specified in the key. Future methods may be defined in future
+ specifications and registered with IANA; a calendar client MUST
+ ignore any method it does not understand, but MUST preserve the
+ method key and URI. This property MUST be omitted if no method is
+ defined (rather than being specified as an empty object). If this
+ property is set, the "participants" property of this calendar object
+ MUST contain at least one participant.
The following methods are defined:
o "imip": The organizer accepts an iMIP [RFC6047] response at this
email address. The value MUST be a "mailto:" URI.
o "web": Opening this URI in a web browser will provide the user
with a page where they can submit a reply to the organizer.
- o "other": The organizer is identified by this URI but the method
- how to submit the RSVP is undefined.
+ o "other": The organizer is identified by this URI the method for
+ submitting the response is undefined.
4.4.5. participants
Type: "Id[Participant]" (optional).
A map of participant ids to participants, describing their
participation in the calendar object.
If this property is set, then the "replyTo" property of this calendar
object MUST define at least one reply method.
@@ -1500,78 +1511,79 @@
A map of participant ids to participants, describing their
participation in the calendar object.
If this property is set, then the "replyTo" property of this calendar
object MUST define at least one reply method.
A Participant object has the following properties:
o @type: "String" (mandatory)
-
Specifies the type of this object. This MUST be "Participant".
o name: "String" (optional)
- The display name of the participant (e.g. "Joe Bloggs").
+ The display name of the participant (e.g., "Joe Bloggs").
o email: "String" (optional)
+
The email address for the participant.
o sendTo: "String[String]" (optional)
Represents methods by which the participant may receive the
invitation and updates to the calendar object.
The keys in the property value are the available methods and MUST
only contain ASCII alphanumeric characters (A-Za-z0-9). The value
- is a URI to use that method. Future methods may be defined in
- future specifications and registered with IANA; a calendar client
- MUST ignore any method it does not understand, but MUST preserve
- the method key and URI. This property MUST be omitted if no
- method is defined (rather than an empty object).
+ is a URI for the method specified in the key. Future methods may
+ be defined in future specifications and registered with IANA; a
+ calendar client MUST ignore any method it does not understand, but
+ MUST preserve the method key and URI. This property MUST be
+ omitted if no method is defined (rather than being specified as an
+ empty object).
The following methods are defined:
* "imip": The participant accepts an iMIP [RFC6047] request at
this email address. The value MUST be a "mailto:" URI. It MAY
be different from the value of the participant's "email"
property.
* "other": The participant is identified by this URI but the
- method how to submit the invitation or update is undefined.
+ method for submitting the invitation is undefined.
o kind: "String" (optional)
What kind of entity this participant is, if known.
- This MUST be either one of the following values, an IANA-
- registered value, or a vendor-specific value. Any value the
- client or server doesn't understand should be treated the same as
- if this property is omitted.
+ This MUST be one of the following values, a value registered in
+ the IANA JSCalendar Enum Registry, or a vendor-specific value.
+ Any value the client or server doesn't understand should be
+ treated the same as if this property is omitted.
* "individual": a single person
* "group": a collection of people invited as a whole
+ * "location": a physical location that needs to be scheduled,
+ e.g., a conference room
- * "resource": a non-human resource, e.g. a projector
-
- * "location": a physical location involved in the calendar object
- that needs to be scheduled, e.g. a conference room.
+ * "resource": a non-human resource other than a location, such as
+ a projector
o roles: "String[Boolean]" (mandatory)
A set of roles that this participant fulfills.
At least one role MUST be specified for the participant. The keys
- in the set MUST be either one of the following values, an IANA-
- registered value, or a vendor-specific value:
+ in the set MUST be one of the following values, a value registered
+ in the IANA JSCalendar Enum Registry, or a vendor-specific value:
* "owner": The participant is an owner of the object. This
signifies they have permission to make changes to it that
affect the other participants. Non-owner participants may only
change properties that just affect themself (for example
setting their own alerts or changing their rsvp status).
* "attendee": The participant is expected to attend.
* "optional": The participant is invited but not required.
@@ -1592,30 +1604,29 @@
o locationId: "String" (optional)
The location at which this participant is expected to be
attending.
If the value does not correspond to any location id in the
"locations" property of the JSCalendar object, this MUST be
treated the same as if the participant's locationId were omitted.
o language: "String" (optional)
-
The language tag as defined in [RFC5646] that best describes the
participant's preferred language, if known.
o participationStatus: "String" (optional, default: "needs-action")
The participation status, if any, of this participant.
- The value MUST be either one of the following values, an IANA-
- registered value, or a vendor-specific value:
+ The value MUST be one of the following values, a value registered
+ in the IANA JSCalendar Enum Registry, or a vendor-specific value:
* "needs-action": No status yet set by the participant.
* "accepted": The invited participant will participate.
* "declined": The invited participant will not participate.
* "tentative": The invited participant may participate.
* "delegated": The invited participant has delegated their
@@ -1629,22 +1640,22 @@
o expectReply: "Boolean" (optional, default: false)
If true, the organizer is expecting the participant to notify them
of their participation status.
o scheduleAgent: "String" (optional, default: "server")
Who is responsible for sending scheduling messages with this
calendar object to the participant.
- The value MUST be either one of the following values, an IANA-
- registered value, or a vendor-specific value:
+ The value MUST be one of the following values, a value registered
+ in the IANA JSCalendar Enum Registry, or a vendor-specific value:
* "server": The calendar server will send the scheduling
messages.
* "client": The calendar client will send the scheduling
messages.
* "none": No scheduling messages are to be sent to this
participant.
@@ -1669,45 +1680,48 @@
o invitedBy: "String" (optional)
The participant id of the participant who invited this one, if
known.
o delegatedTo: "String[Boolean]" (optional)
A set of participant ids that this participant has delegated their
participation to. Each key in the set MUST be the id of a
- participant. The value for each key in the set MUST be true.
- This MUST be omitted if none (rather than an empty set).
+ participant. The value for each key in the set MUST be true. If
+ there are no delegates, this MUST be omitted (rather than
+ specified as an empty set).
o delegatedFrom: "String[Boolean]" (optional)
A set of participant ids that this participant is acting as a
delegate for. Each key in the set MUST be the id of a
- participant. The value for each key in the set MUST be true.
- This MUST be omitted if none (rather than an empty set).
+ participant. The value for each key in the set MUST be true. If
+ there are no delegators, this MUST be omitted (rather than
+ specified as an empty set).
o memberOf: "String[Boolean]" (optional)
A set of group participants that were invited to this calendar
object, which caused this participant to be invited due to their
- membership of the group(s). Each key in the set MUST be the id of
+ membership in the group(s). Each key in the set MUST be the id of
a participant. The value for each key in the set MUST be true.
- This MUST be omitted if none (rather than an empty set).
+ If there are no groups, this MUST be omitted (rather than
+ specified as an empty set).
o linkIds: "String[Boolean]" (optional)
A set of links to more information about this participant, for
example in vCard format. The keys in the set MUST be the id of a
Link object in the calendar object's "links" property. The value
- for each key in the set MUST be true. This MUST be omitted if
- none (rather than an empty set).
+ for each key in the set MUST be true. If there are no links, this
+ MUST be omitted (rather than specified as an empty set).
o progress: "String" (optional). This is only allowed if the
Participant is part of a JSTask. It represents the progress of
the participant for this task, if known. This property MUST NOT
be set if the "participationStatus" of this participant is any
value other than "accepted". See Section 5.2.4 for allowed values
and semantics.
o progressUpdated: "UTCDateTime" (optional). Specifies the date-
time the progress property was last set on this participant. This
@@ -1734,23 +1748,22 @@
display or send to the user for this calendar object.
An Alert Object has the following properties:
o @type: "String" (mandatory)
Specifies the type of this object. This MUST be "Alert".
o trigger: "OffsetTrigger|AbsoluteTrigger|UnknownTrigger"
(mandatory)
-
Defines when to trigger the alert. New types may be defined in
- future RFCs.
+ future documents.
An *OffsetTrigger* object has the following properties:
* @type: "String" (mandatory)
Specifies the type of this object. This MUST be
"OffsetTrigger".
* offset: "SignedDuration" (mandatory).
@@ -1780,23 +1793,23 @@
Specifies the type of this object. This MUST be
"AbsoluteTrigger".
* when: "UTCDateTime" (mandatory).
Defines a specific UTC date-time when the alert is triggered.
An *UnknownTrigger* object is an object that contains a *@type*
property whose value is not recognized (i.e., not "OffsetTrigger"
or "AbsoluteTrigger"), plus zero or more other properties. This
- is for compatibility with client extensions and future RFCs.
- Implementations SHOULD NOT trigger for trigger types they do not
- understand, but MUST preserve them.
+ is for compatibility with client extensions and future
+ specifications. Implementations SHOULD NOT trigger for trigger
+ types they do not understand, but MUST preserve them.
o acknowledged: "UTCDateTime" (optional)
This records when an alert was last acknowledged. This is set
when the user has dismissed the alert; other clients that sync
this property SHOULD automatically dismiss or suppress duplicate
alerts (alerts with the same alert id that triggered on or before
this date-time).
For a recurring calendar object, the "acknowledged" property of
@@ -1807,44 +1820,44 @@
the user sees them, for example email based alerts. For those
kinds of alerts, this property SHOULD be set immediately when the
alert is triggered and the action successfully carried out.
o relatedTo: "String[Relation]" (optional)
Relates this alert to other alerts in the same JSCalendar object.
If the user wishes to snooze an alert, the application SHOULD
create an alert to trigger after snoozing. All snooze alerts
SHOULD set a relation to the identifier of the original alert.
- The Relation object SHOULD set the "parent" relation type, but MAY
- be empty.
+ The Relation object SHOULD set the "parent" relation type.
o action: "String" (optional, default: "display")
Describes how to alert the user.
- The value MUST be at most one of the following values, an IANA-
- registered value, or a vendor-specific value:
+ The value MUST be at most one of the following values, a value
+ registered in the IANA JSCalendar Enum Registry, or a vendor-
+ specific value:
* "display": The alert should be displayed as appropriate for the
current device and user context.
* "email": The alert should trigger an email sent out to the
user, notifying about the alert. This action is typically only
appropriate for server implementations.
4.6. Multilingual Properties
4.6.1. localizations
Type: "String[PatchObject]" (optional).
- A map of [RFC5646] language tags to patch objects, which localize the
+ A map of language tags [RFC5646] to patch objects, which localize the
calendar object into the locale of the respective language tag.
See the description of PatchObject (Section 1.4.8) for the structure
of the PatchObject. The patches are applied to the top-level
calendar object. In addition, the "locale" property of the patched
object is set to the language tag. All pointers for patches MUST end
with one of the following suffixes; any patch that does not follow
this MUST be ignored unless otherwise specified in a future RFC:
o title
@@ -1874,32 +1888,32 @@
Identifies the time zone the object is scheduled in, or null for
floating time. This is either a name from the IANA Time Zone
Database [TZDB] or the id of a custom time zone from the "timeZones"
property (see Section 1.4.9). If omitted, this MUST be presumed to
be null (i.e., floating time).
4.7.2. timeZones
Type: "String[TimeZone]" (optional).
- Maps identifiers of custom time zones to their time zone definition.
+ Maps identifiers of custom time zones to their time zone definitions.
The following restrictions apply for each key in the map:
o It MUST start with the "/" character (ASCII decimal 47; also see
Sections 3.2.19 of [RFC5545] and 3.6. of [RFC7808] for discussion
of the forward slash character in time zone identifiers).
o It MUST be a valid "paramtext" value as specified in Section 3.1.
of [RFC5545].
o At least one other property in the same JSCalendar object MUST
- reference a time zone using this identifier (i.e. orphaned time
+ reference a time zone using this identifier (i.e., orphaned time
zones are not allowed).
An identifier need only be unique to this JSCalendar object.
A TimeZone object maps a VTIMEZONE component from iCalendar [RFC5545]
and the semantics are as defined there. A valid time zone MUST
define at least one transition rule in the "standard" or "daylight"
property. Its properties are:
o @type: "String" (mandatory)
@@ -2006,31 +2021,31 @@
discontinuity in the event's time zone, for example a change from
standard time to daylight-savings time. Leap seconds MUST NOT be
considered when computing an exact duration. When computing an exact
duration, the greatest order time components MUST be added first,
that is, the number of days MUST be added first, followed by the
number of hours, number of minutes, and number of seconds.
Fractional seconds MUST be added last. These semantics match the
iCalendar DURATION value type ([RFC5545], Section 3.3.6).
A JSEvent MAY involve start and end locations that are in different
- time zones (e.g. a trans-continental flight). This can be expressed
+ time zones (e.g., a trans-continental flight). This can be expressed
using the "relativeTo" and "timeZone" properties of the JSEvent's
Location objects (see Section 4.2.5).
5.1.3. status
Type: "String" (optional, default: "confirmed").
The scheduling status (Section 4.4) of a JSEvent. If set, it MUST be
- one of the following values, an IANA-registered value, or a vendor-
- specific value:
+ one of the following values, a value registered in the IANA
+ JSCalendar Enum Registry, or a vendor-specific value:
o "confirmed": Indicates the event is definitely happening.
o "cancelled": Indicates the event has been cancelled.
o "tentative": Indicates the event may happen.
5.2. JSTask Properties
In addition to the common JSCalendar object properties (Section 4) a
@@ -2067,22 +2082,22 @@
is "completed".
o "failed": if at least one "progress" property value of a
participant is "failed".
o "in-process": if at least one "progress" property value of a
participant is "in-process".
o "needs-action": If none of the other criteria match.
- If set, it MUST be one of the following values, an IANA-registered
- value, or a vendor-specific value:
+ If set, it MUST be one of the following values, a value registered in
+ the IANA JSCalendar Enum Registry, or a vendor-specific value:
o "needs-action": Indicates the task needs action.
o "in-process": Indicates the task is in process.
o "completed": Indicates the task is completed.
o "failed": Indicates the task failed.
o "cancelled": Indicates the task was cancelled.
@@ -2294,37 +2309,37 @@
"duration": "PT30M",
"recurrenceRules": [{
"@type": "RecurrenceRule",
"frequency": "daily"
}]
}
6.8. Event with multiple locations and localization
This example illustrates an event that happens at both a physical and
- a virtual location. Fans can see a live convert on premises or
+ a virtual location. Fans can see a live concert on premises or
online. The event title and descriptions are localized.
{
"...": "",
"title": "Live from Music Bowl: The Band",
"description": "Go see the biggest music event ever!",
"locale": "en",
"start": "2018-07-04T17:00:00",
"timeZone": "America/New_York",
"duration": "PT3H",
"locations": {
"c0503d30-8c50-4372-87b5-7657e8e0fedd": {
"@type": "Location",
"name": "The Music Bowl",
"description": "Music Bowl, Central Park, New York",
- "coordinates": "geo:40.7829,73.9654"
+ "coordinates": "geo:40.7829,-73.9654"
}
},
"virtualLocations": {
"6f3696c6-1e07-47d0-9ce1-f50014b0041a": {
"@type": "VirtualLocation",
"name": "Free live Stream from Music Bowl",
"uri": "https://stream.example.com/the_band_2018"
}
},
"localizations": {
@@ -2452,38 +2467,38 @@
"2018-03-08T09:00:00": {
"participants/dG9tQGZvb2Jhci5xlLmNvbQ/participationStatus":
"declined"
}
}
}
7. Security Considerations
Calendaring and scheduling information is very privacy-sensitive.
- The transmission of such information must be careful to protect it
- from possible threats, such as eavesdropping, replay, message
- insertion, deletion, modification, and man-in-the-middle attacks.
- This document just defines the data format; such considerations are
- primarily the concern of the API or method of storage and
- transmission of such files.
+ The transmission of such information must be done carefully to
+ protect it from possible threats, such as eavesdropping, replay,
+ message insertion, deletion, modification, and man-in-the-middle
+ attacks. This document just defines the data format; such
+ considerations are primarily the concern of the API or method of
+ storage and transmission of such files.
7.1. Expanding Recurrences
A recurrence rule may produce infinite occurrences of an event.
Implementations MUST handle expansions carefully to prevent
accidental or deliberate resource exhaustion.
Conversely, a recurrence rule may be specified that does not expand
to anything. It is not always possible to tell this through static
analysis of the rule, so implementations MUST be careful to avoid
- getting stuck in an infinite loop, or otherwise exhausting resources,
- searching for the next occurrence.
+ getting stuck in infinite loops, or otherwise exhausting resources
+ while searching for the next occurrence.
7.2. JSON Parsing
The Security Considerations of [RFC8259] apply to the use of JSON as
the data interchange format.
As for any serialization format, parsers need to thoroughly check the
syntax of the supplied data. JSON uses opening and closing tags for
several types and structures, and it is possible that the end of the
supplied data will be reached when scanning for a matching closing
@@ -2509,21 +2524,21 @@
7.3. URI Values
Several JSCalendar properties contain URIs as values, and processing
these properties requires extra care. Section 7 of [RFC3986]
discusses security risk related to URIs.
8. IANA Considerations
8.1. Media Type Registration
- This document defines a MIME media type for use with JSCalendar data
+ This document defines a media type for use with JSCalendar data
formatted in JSON.
Type name: application
Subtype name: jscalendar+json
Required parameters: type
The "type" parameter conveys the type of the JSCalendar data in
the body part, with the value being one of "jsevent", "jstask", or
@@ -2554,21 +2569,21 @@
Additional information:
Magic number(s): N/A
File extensions(s): N/A
Macintosh file type code(s): N/A
Person & email address to contact for further information:
- calext@ietf.org
+ calsify@ietf.org
Intended usage: COMMON
Restrictions on usage: N/A
Author: See the "Author's Address" section of this document.
Change controller: IETF
8.2. Creation of "JSCalendar Properties" Registry
@@ -2627,29 +2642,26 @@
collisions and encouraging the submitter to document security and
privacy considerations. For a common-use registration, the DE is
expected to confirm that suitable documentation, as described in
Section 4.6 of [RFC8126], is available to ensure interoperability.
This preferably takes the form of an RFC, but for simple definitions
a description in the registry may be sufficient. The DE should also
verify that the property name does not conflict with work that is
active or already published within the IETF. A published
specification is not required for reserved or obsolete registrations.
- Before a period of 30 days has passed, the DE will either approve or
- deny the registration request and publish a notice of the decision to
- the Calext WG mailing list or its successor, as well as inform IANA.
- A denial notice must be justified by an explanation, and, in the
- cases where it is possible, concrete suggestions on how the request
- can be modified so as to become acceptable should be provided.
-
- If the DE does not respond within 30 days, the registrant may request
- the IESG take action to process the request in a timely manner.
+ The DE will either approve or deny the registration request and
+ publish a notice of the decision to the Calext WG mailing list or its
+ successor, as well as inform IANA. A denial notice must be justified
+ by an explanation, and, in the cases where it is possible, concrete
+ suggestions on how the request can be modified so as to become
+ acceptable should be provided.
8.2.4. Change Procedures
Once a JSCalendar property has been published by the IANA, the change
controller may request a change to its definition. The same
procedure that would be appropriate for the original registration
request is used to process a change request.
JSCalendar property registrations may not be deleted; properties that
are no longer believed appropriate for use can be declared obsolete
@@ -2660,32 +2672,27 @@
requested only when there are serious omissions or errors in the
published specification, as such changes may cause interoperability
issues. When review is required, a change request may be denied if
it renders entities that were valid under the previous definition
invalid under the new definition.
The owner of a JSCalendar property may pass responsibility to another
person or agency by informing the IANA; this can be done without
discussion or review.
- The IESG may reassign responsibility for a JSCalendar property. The
- most common case of this will be to enable changes to be made to a
- registration where the author of the registration has died, moved out
- of contact, or is otherwise unable to make changes that are important
- to the community.
-
8.2.5. JMAP Properties Registry Template
o Property Name: The name of the property. The property name MUST
- NOT already be registered for any of the objects listed in
- Context. Objects not listed in Context MAY already have
- registered a different property with the same name.
+ NOT already be registered for any of the object types listed in
+ the "Property Context" field of this registration. Other object
+ types MAY already have registered a different property with the
+ same name.
o Property Type: The type of this property, using type signatures as
specified in Section 1.3. The property type MUST be registed in
the Type Registry.
o Property Context: A comma-separated list of JSCalendar object
types this property is allowed on.
o Reference or Description: A brief description or RFC number and
section reference where the property is specified (omitted for
@@ -3359,141 +3366,156 @@
Table 14
9. Acknowledgments
The authors would like to thank the members of CalConnect for their
valuable contributions. This specification originated from the work
of the API technical committee of CalConnect, the Calendaring and
Scheduling Consortium.
-10. Informative References
+10. References
- [COLORS] "CSS Color Module", .
+10.1. Normative References
- [LINKRELS]
- "IANA Link Relation Types",
- .
+ [CLDR] "Unicode Common Locale Data Repository",
+ .
- [MIME] "IANA Media Types", .
+ [COLORS] "CSS Color Module", .
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
.
[RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource
Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998,
.
+ [RFC2397] Masinter, L., "The "data" URL scheme", RFC 2397,
+ DOI 10.17487/RFC2397, August 1998,
+ .
+
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
.
- [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,
- .
-
- [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
- Unique IDentifier (UUID) URN Namespace", RFC 4122,
- DOI 10.17487/RFC4122, July 2005,
- .
-
[RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types
Registry", RFC 4589, DOI 10.17487/RFC4589, July 2006,
.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
.
- [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault,
- "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791,
- DOI 10.17487/RFC4791, March 2007,
- .
-
[RFC5545] Desruisseaux, B., Ed., "Internet Calendaring and
Scheduling Core Object Specification (iCalendar)",
RFC 5545, DOI 10.17487/RFC5545, September 2009,
.
- [RFC5546] Daboo, C., Ed., "iCalendar Transport-Independent
- Interoperability Protocol (iTIP)", RFC 5546,
- DOI 10.17487/RFC5546, December 2009,
- .
-
[RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
September 2009, .
[RFC5870] Mayrhofer, A. and C. Spanring, "A Uniform Resource
Identifier for Geographic Locations ('geo' URI)",
RFC 5870, DOI 10.17487/RFC5870, June 2010,
.
- [RFC6047] Melnikov, A., Ed., "iCalendar Message-Based
- Interoperability Protocol (iMIP)", RFC 6047,
- DOI 10.17487/RFC6047, December 2010,
- .
-
[RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
.
[RFC6901] Bryan, P., Ed., Zyp, K., and M. Nottingham, Ed.,
"JavaScript Object Notation (JSON) Pointer", RFC 6901,
DOI 10.17487/RFC6901, April 2013,
.
- [RFC7265] Kewisch, P., Daboo, C., and M. Douglass, "jCal: The JSON
- Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May
- 2014, .
-
[RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493,
DOI 10.17487/RFC7493, March 2015,
.
- [RFC7529] Daboo, C. and G. Yakushev, "Non-Gregorian Recurrence Rules
- in the Internet Calendaring and Scheduling Core Object
- Specification (iCalendar)", RFC 7529,
- DOI 10.17487/RFC7529, May 2015,
- .
-
- [RFC7808] Douglass, M. and C. Daboo, "Time Zone Data Distribution
- Service", RFC 7808, DOI 10.17487/RFC7808, March 2016,
- .
-
- [RFC7986] Daboo, C., "New Properties for iCalendar", RFC 7986,
- DOI 10.17487/RFC7986, October 2016,
- .
-
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
.
+ [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
+ 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
+ May 2017, .
+
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
.
[RFC8288] Nottingham, M., "Web Linking", RFC 8288,
DOI 10.17487/RFC8288, October 2017,
.
[TZDB] "IANA Time Zone Database",
.
+10.2. Informative References
+
+ [LINKRELS]
+ "IANA Link Relation Types",
+ .
+
+ [MIME] "IANA Media Types", .
+
+ [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,
+ .
+
+ [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
+ Unique IDentifier (UUID) URN Namespace", RFC 4122,
+ DOI 10.17487/RFC4122, July 2005,
+ .
+
+ [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault,
+ "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791,
+ DOI 10.17487/RFC4791, March 2007,
+ .
+
+ [RFC5546] Daboo, C., Ed., "iCalendar Transport-Independent
+ Interoperability Protocol (iTIP)", RFC 5546,
+ DOI 10.17487/RFC5546, December 2009,
+ .
+
+ [RFC6047] Melnikov, A., Ed., "iCalendar Message-Based
+ Interoperability Protocol (iMIP)", RFC 6047,
+ DOI 10.17487/RFC6047, December 2010,
+ .
+
+ [RFC7265] Kewisch, P., Daboo, C., and M. Douglass, "jCal: The JSON
+ Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May
+ 2014, .
+
+ [RFC7529] Daboo, C. and G. Yakushev, "Non-Gregorian Recurrence Rules
+ in the Internet Calendaring and Scheduling Core Object
+ Specification (iCalendar)", RFC 7529,
+ DOI 10.17487/RFC7529, May 2015,
+ .
+
+ [RFC7808] Douglass, M. and C. Daboo, "Time Zone Data Distribution
+ Service", RFC 7808, DOI 10.17487/RFC7808, March 2016,
+ .
+
+ [RFC7986] Daboo, C., "New Properties for iCalendar", RFC 7986,
+ DOI 10.17487/RFC7986, October 2016,
+ .
+
Authors' Addresses
Neil Jenkins
Fastmail
PO Box 234
Collins St West
Melbourne VIC 8007
Australia
Email: neilj@fastmailteam.com