Internet Assigned Numbers Authority

iCalendar Element Registries

Created
2009-04-29
Last Updated
2022-08-19
Note
A Standards Track RFC is required for registration of iCalendar elements that 
modify elements previously documented in a Standards Track RFC.
Available Formats

XML
HTML
Plain text

Registries included below

Components

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Component Status Reference
VCALENDAR Current [RFC5545], Section 3.4
VEVENT Current [RFC5545], Section 3.6.1
VTODO Current [RFC5545], Section 3.6.2
VJOURNAL Current [RFC5545], Section 3.6.3
VFREEBUSY Current [RFC5545], Section 3.6.4
VTIMEZONE Current [RFC5545], Section 3.6.5
VALARM Current [RFC5545], Section 3.6.6
STANDARD Current [RFC5545], Section 3.6.5
DAYLIGHT Current [RFC5545], Section 3.6.5
VAVAILABILITY Current [RFC7953], Section 3.1
AVAILABLE Current [RFC7953], Section 3.1
PARTICIPANT Current [RFC9073], Section 7.1
VLOCATION Current [RFC9073], Section 7.2
VRESOURCE Current [RFC9073], Section 7.3

Properties

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Property Status Reference
CALSCALE Current [RFC5545], Section 3.7.1
METHOD Current [RFC5545], Section 3.7.2
PRODID Current [RFC5545], Section 3.7.3
VERSION Current [RFC5545], Section 3.7.4
ATTACH Current [RFC5545], Section 3.8.1.1
CATEGORIES Current [RFC5545], Section 3.8.1.2; [RFC7986], Section 5.6
CLASS Current [RFC5545], Section 3.8.1.3
COMMENT Current [RFC5545], Section 3.8.1.4
DESCRIPTION Current [RFC5545], Section 3.8.1.5; [RFC7986], Section 5.2
GEO Current [RFC5545], Section 3.8.1.6
LOCATION Current [RFC5545], Section 3.8.1.7
PERCENT-COMPLETE Current [RFC5545], Section 3.8.1.8
PRIORITY Current [RFC5545], Section 3.8.1.9
RESOURCES Current [RFC5545], Section 3.8.1.10
STATUS Current [RFC5545], Section 3.8.1.11
SUMMARY Current [RFC5545], Section 3.8.1.12
COMPLETED Current [RFC5545], Section 3.8.2.1
DTEND Current [RFC5545], Section 3.8.2.2
DUE Current [RFC5545], Section 3.8.2.3
DTSTART Current [RFC5545], Section 3.8.2.4
DURATION Current [RFC5545], Section 3.8.2.5
FREEBUSY Current [RFC5545], Section 3.8.2.6
TRANSP Current [RFC5545], Section 3.8.2.7
TZID Current [RFC5545], Section 3.8.3.1
TZNAME Current [RFC5545], Section 3.8.3.2
TZOFFSETFROM Current [RFC5545], Section 3.8.3.3
TZOFFSETTO Current [RFC5545], Section 3.8.3.4
TZURL Current [RFC5545], Section 3.8.3.5
ATTENDEE Current [RFC5545], Section 3.8.4.1
CONTACT Current [RFC5545], Section 3.8.4.2
ORGANIZER Current [RFC5545], Section 3.8.4.3
RECURRENCE-ID Current [RFC5545], Section 3.8.4.4
RELATED-TO Current [RFC5545], Section 3.8.4.5; [RFC9253], Section 9.1
URL Current [RFC5545], Section 3.8.4.6; [RFC7986], Section 5.5
UID Current [RFC5545], Section 3.8.4.7; [RFC7986], Section 5.3
EXDATE Current [RFC5545], Section 3.8.5.1
EXRULE Deprecated [RFC2445], Section 4.8.5.2
RDATE Current [RFC5545], Section 3.8.5.2
RRULE Current [RFC5545], Section 3.8.5.3
ACTION Current [RFC5545], Section 3.8.6.1
REPEAT Current [RFC5545], Section 3.8.6.2
TRIGGER Current [RFC5545], Section 3.8.6.3
CREATED Current [RFC5545], Section 3.8.7.1
DTSTAMP Current [RFC5545], Section 3.8.7.2
LAST-MODIFIED Current [RFC5545], Section 3.8.7.3; [RFC7986], Section 5.4
SEQUENCE Current [RFC5545], Section 3.8.7.4
REQUEST-STATUS Current [RFC5545], Section 3.8.8.3
XML Current [RFC6321], Section 4.2
TZUNTIL Current [RFC7808], Section 7.1
TZID-ALIAS-OF Current [RFC7808], Section 7.2
BUSYTYPE Current [RFC7953], Section 3.2
NAME Current [RFC7986], Section 5.1
REFRESH-INTERVAL Current [RFC7986], Section 5.7
SOURCE Current [RFC7986], Section 5.8
COLOR Current [RFC7986], Section 5.9
IMAGE Current [RFC7986], Section 5.10
CONFERENCE Current [RFC7986], Section 5.11
CALENDAR-ADDRESS Current [RFC9073], Section 6.4
LOCATION-TYPE Current [RFC9073], Section 6.1
PARTICIPANT-TYPE Current [RFC9073], Section 6.2
RESOURCE-TYPE Current [RFC9073], Section 6.3
STRUCTURED-DATA Current [RFC9073], Section 6.6
STYLED-DESCRIPTION Current [RFC9073], Section 6.5
ACKNOWLEDGED Current [RFC9074], Section 6.1
PROXIMITY Current [RFC9074], Section 8.1
CONCEPT Current [RFC9253], Section 8.1
LINK Current [RFC9253], Section 8.2
REFID Current [RFC9253], Section 8.3

Parameters

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Parameter Status Reference
ALTREP Current [RFC5545], Section 3.2.1
CN Current [RFC5545], Section 3.2.2
CUTYPE Current [RFC5545], Section 3.2.3
DELEGATED-FROM Current [RFC5545], Section 3.2.4
DELEGATED-TO Current [RFC5545], Section 3.2.5
DIR Current [RFC5545], Section 3.2.6
ENCODING Current [RFC5545], Section 3.2.7
FMTTYPE Current [RFC5545], Section 3.2.8
FBTYPE Current [RFC5545], Section 3.2.9
LANGUAGE Current [RFC5545], Section 3.2.10
MEMBER Current [RFC5545], Section 3.2.11
PARTSTAT Current [RFC5545], Section 3.2.12
RANGE Current [RFC5545], Section 3.2.13
RELATED Current [RFC5545], Section 3.2.14
RELTYPE Current [RFC5545], Section 3.2.15
ROLE Current [RFC5545], Section 3.2.16
RSVP Current [RFC5545], Section 3.2.17
SCHEDULE-AGENT Current [RFC6638], Section 7.1
SCHEDULE-FORCE-SEND Current [RFC6638], Section 7.2
SCHEDULE-STATUS Current [RFC6638], Section 7.3
SENT-BY Current [RFC5545], Section 3.2.18
TZID Current [RFC5545], Section 3.2.19
VALUE Current [RFC5545], Section 3.2.20
DISPLAY Current [RFC7986], Section 6.1
EMAIL Current [RFC7986], Section 6.2
FEATURE Current [RFC7986], Section 6.3
LABEL Current [RFC7986], Section 6.4
SIZE Current [RFC8607], Section 4.1
FILENAME Current [RFC8607], Section 4.2
MANAGED-ID Current [RFC8607], Section 4.3
ORDER Current [RFC9073], Section 5.1
SCHEMA Current [RFC9073], Section 5.2
DERIVED Current [RFC9073], Section 5.3
GAP Current [RFC9253], Section 6.2
LINKREL Current [RFC9253], Section 6.1

Value Data Types

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Note
A Standards Track RFC is REQUIRED for the registration of new Value Data Types that modify
existing properties.
Available Formats

CSV
Value Data Type Status Reference
BINARY Current [RFC5545], Section 3.3.1
BOOLEAN Current [RFC5545], Section 3.3.2
CAL-ADDRESS Current [RFC5545], Section 3.3.3
DATE Current [RFC5545], Section 3.3.4
DATE-TIME Current [RFC5545], Section 3.3.5
DURATION Current [RFC5545], Section 3.3.6
FLOAT Current [RFC5545], Section 3.3.7
INTEGER Current [RFC5545], Section 3.3.8
PERIOD Current [RFC5545], Section 3.3.9
RECUR Current [RFC5545], Section 3.3.10
TEXT Current [RFC5545], Section 3.3.11
TIME Current [RFC5545], Section 3.3.12
UNKNOWN Reserved - Do not use [RFC7265], Section 5
URI Current [RFC5545], Section 3.3.13
UTC-OFFSET Current [RFC5545], Section 3.3.14
XML-REFERENCE Current [RFC9253], Section 7
UID Current [RFC9253], Section 7

Calendar User Types

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Calendar User Type Status Reference
INDIVIDUAL Current [RFC5545], Section 3.2.3
GROUP Current [RFC5545], Section 3.2.3
RESOURCE Current [RFC5545], Section 3.2.3
ROOM Current [RFC5545], Section 3.2.3
UNKNOWN Current [RFC5545], Section 3.2.3

Free/Busy Time Types

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Free/Busy Time Type Status Reference
FREE Current [RFC5545], Section 3.2.9
BUSY Current [RFC5545], Section 3.2.9
BUSY-UNAVAILABLE Current [RFC5545], Section 3.2.9
BUSY-TENTATIVE Current [RFC5545], Section 3.2.9

Participation Statuses

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Note
A Standards Track RFC is REQUIRED for the registration of Participation Status values 
to be used in "VEVENT" calendar components.
Available Formats

CSV
Participation Status Status Reference
NEEDS-ACTION Current [RFC5545], Section 3.2.12
ACCEPTED Current [RFC5545], Section 3.2.12
DECLINED Current [RFC5545], Section 3.2.12
TENTATIVE Current [RFC5545], Section 3.2.12
DELEGATED Current [RFC5545], Section 3.2.12
COMPLETED Current [RFC5545], Section 3.2.12
IN-PROCESS Current [RFC5545], Section 3.2.12

Relationship Types

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Relationship Type Status Reference
CHILD Current [RFC5545], Section 3.2.15
PARENT Current [RFC5545], Section 3.2.15
SIBLING Current [RFC5545], Section 3.2.15
SNOOZE Current [RFC9074], Section 7.1
CONCEPT Current [RFC9253], Section 5
DEPENDS-ON Current [RFC9253], Section 5
FINISHTOFINISH Current [RFC9253], Section 4
FINISHTOSTART Current [RFC9253], Section 4
FIRST Current [RFC9253], Section 5
NEXT Current [RFC9253], Section 5
REFID Current [RFC9253], Section 5
STARTTOFINISH Current [RFC9253], Section 4
STARTTOSTART Current [RFC9253], Section 4

Participation Roles

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Role Type Status Reference
CHAIR Current [RFC5545], Section 3.2.16
REQ-PARTICIPANT Current [RFC5545], Section 3.2.16
OPT-PARTICIPANT Current [RFC5545], Section 3.2.16
NON-PARTICIPANT Current [RFC5545], Section 3.2.16

Actions

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Action Status Reference
AUDIO Current [RFC5545], Section 3.8.6.1
DISPLAY Current [RFC5545], Section 3.8.6.1
EMAIL Current [RFC5545], Section 3.8.6.1
PROCEDURE Deprecated [RFC2445], Section 4.8.6.1

Classifications

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Classification Status Reference
PUBLIC Current [RFC5545], Section 3.8.1.3
PRIVATE Current [RFC5545], Section 3.8.1.3
CONFIDENTIAL Current [RFC5545], Section 3.8.1.3

Methods

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5545]
Available Formats

CSV
Method Status Reference
PUBLISH Current [RFC5546]
REQUEST Current [RFC5546]
REPLY Current [RFC5546]
ADD Current [RFC5546]
CANCEL Current [RFC5546]
REFRESH Current [RFC5546]
COUNTER Current [RFC5546]
DECLINECOUNTER Current [RFC5546]

REQUEST-STATUS Values

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Bernard Desruisseaux, Cyrus Daboo, Ken Murchison, Mike Douglass
Reference
[RFC5546]
Available Formats

CSV
Status Code Status Reference
1.0 Current [RFC6638], Section 3.2.9.1
1.1 Current [RFC6638], Section 3.2.9.2
1.2 Current [RFC6638], Section 3.2.9.3
2.0 Current [RFC5546], Section 3.6.1
2.1 Current [RFC5546], Section 3.6.2
2.2 Current [RFC5546], Section 3.6.3
2.3 Current [RFC5546], Section 3.6.4
2.4 Current [RFC5546], Section 3.6.5
2.5 Current [RFC5546], Section 3.6.6
2.6 Current [RFC5546], Section 3.6.7
2.7 Current [RFC5546], Section 3.6.8
2.8 Current [RFC5546], Section 3.6.9
2.9 Current [RFC5546], Section 3.6.10
2.10 Current [RFC5546], Section 3.6.11
2.11 Current [RFC5546], Section 3.6.12
3.0 Current [RFC5546], Section 3.6.13
3.1 Current [RFC5546], Section 3.6.14
3.2 Current [RFC5546], Section 3.6.15
3.3 Current [RFC5546], Section 3.6.16
3.4 Current [RFC5546], Section 3.6.17
3.5 Current [RFC5546], Section 3.6.18
3.6 Current [RFC5546], Section 3.6.19
3.7 Current [RFC5546], Section 3.6.20
3.8 Current [RFC5546], Section 3.6.21
3.9 Current [RFC5546], Section 3.6.22
3.10 Current [RFC5546], Section 3.6.23
3.11 Current [RFC5546], Section 3.6.24
3.12 Current [RFC5546], Section 3.6.25
3.13 Current [RFC5546], Section 3.6.26
3.14 Current [RFC5546], Section 3.6.27
4.0 Current [RFC5546], Section 3.6.28
5.0 Current [RFC5546], Section 3.6.29
5.1 Current [RFC5546], Section 3.6.30
5.2 Current [RFC5546], Section 3.6.31
5.3 Current [RFC5546], Section 3.6.32

Schedule Agent Values Registry

Registration Procedure(s)
Expert Review with RFC Required
Reference
[RFC6638]
Available Formats

CSV
Schedule Agent Status Reference
SERVER Current [RFC6638], Section 7.1
CLIENT Current [RFC6638], Section 7.1
NONE Current [RFC6638], Section 7.1

Schedule Force Send Values Registry

Registration Procedure(s)
Expert Review with RFC Required
Reference
[RFC6638]
Available Formats

CSV
Schedule Force Send Status Reference
REQUEST Current [RFC6638], Section 7.2
REPLY Current [RFC6638], Section 7.2

Display Types

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Unassigned
Reference
[RFC7986]
Available Formats

CSV
Display Type Status Reference
BADGE Current [RFC7986], Section 6.1
GRAPHIC Current [RFC7986], Section 6.1
FULLSIZE Current [RFC7986], Section 6.1
THUMBNAIL Current [RFC7986], Section 6.1

Feature Types

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Unassigned
Reference
[RFC7986]
Available Formats

CSV
Name Status Reference
AUDIO Current [RFC7986], Section 6.3
CHAT Current [RFC7986], Section 6.3
FEED Current [RFC7986], Section 6.3
MODERATOR Current [RFC7986], Section 6.3
PHONE Current [RFC7986], Section 6.3
SCREEN Current [RFC7986], Section 6.3
VIDEO Current [RFC7986], Section 6.3

Participant Types

Registration Procedure(s)
Expert Review
Expert(s)
Ken Murchison, Michael Douglass
Reference
[RFC9073]
Available Formats

CSV
Participant Type Status Reference
ACTIVE Current [RFC9073], Section 6.2
INACTIVE Current [RFC9073], Section 6.2
SPONSOR Current [RFC9073], Section 6.2
CONTACT Current [RFC9073], Section 6.2
BOOKING-CONTACT Current [RFC9073], Section 6.2
EMERGENCY-CONTACT Current [RFC9073], Section 6.2
PUBLICITY-CONTACT Current [RFC9073], Section 6.2
PLANNER-CONTACT Current [RFC9073], Section 6.2
PERFORMER Current [RFC9073], Section 6.2
SPEAKER Current [RFC9073], Section 6.2

Resource Types

Registration Procedure(s)
Expert Review
Expert(s)
Ken Murchison, Michael Douglass
Reference
[RFC9073]
Available Formats

CSV
Resource Type Status Reference
PROJECTOR Current [RFC9073], Section 6.3
ROOM Current [RFC9073], Section 6.3
REMOTE-CONFERENCE-AUDIO Current [RFC9073], Section 6.3
REMOTE-CONFERENCE-VIDEO Current [RFC9073], Section 6.3

Proximity Values

Registration Procedure(s)
Expert Review with RFC Required
Expert(s)
Ken Murchison, Michael Douglass
Reference
[RFC9074]
Available Formats

CSV
Value Status Reference
ARRIVE Current [RFC9074], Section 8.1
DEPART Current [RFC9074], Section 8.1
CONNECT Current [RFC9074], Section 8.1
DISCONNECT Current [RFC9074], Section 8.1