• The attributes of the calendar entry represented must be described as simple key-value pairs. Simple events are simple to represent; complex events can be modeled accurately.
• Wherever possible, there should be only one way to express the desired semantics, reducing complexity.
• The data model should avoid ambiguities, which often lead to interoperability issues between implementations.
• The data model should be generally compatible with the iCalendar data format [RFC 5545] [RFC 7986] and extensions, but the specification should add new attributes where the iCalendar format currently lacks 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.
• Extensions, such as new properties and components, should not require updates to this document.

• iCalendar defines various formats for local times, UTC, and dates.
• iCalendar requires custom time zone definitions within a single calendar component.
• iCalendar's definition of recurrence rules is ambiguous and has resulted in differing interpretations, even between experienced calendar developers.
• The iCalendar format itself causes interoperability issues due to misuse of CRLF-terminated strings, line continuations, and subtle differences among iCalendar parsers.

*:

The type is undefined (the value could be any type, although permitted values may be constrained by the context of this value).

String:

This is the JSON string type.

Number:

This is the JSON number type.

Boolean:

This is the JSON boolean type.

A[B]:

The keys are all of type A and the values are all of type B for a JSON object.

A[]:

There is an array of values of type A

A|B:

The value is either of type A or of type B.

    dur-secfrac = "." 1*DIGIT
    dur-second  = 1*DIGIT [dur-secfrac] "S"
    dur-minute  = 1*DIGIT "M" [dur-second]
    dur-hour    = 1*DIGIT "H" [dur-minute]
    dur-time    = "T" (dur-hour / dur-minute / dur-second)
    dur-day     = 1*DIGIT "D"
    dur-week    = 1*DIGIT "W"
    dur-cal     = (dur-week [dur-day] / dur-day)

    duration    = "P" (dur-cal [dur-time] / dur-time)

1. If a time zone applies to the LocalDateTime, convert it to a UTCDateTime following the semantics in Section 1.4.5.
2. Add any hour, minute, or second components of the duration (in absolute time).
3. Convert the resulting UTCDateTime back to a LocalDateTime in the time zone that applies.

1. Subtract any hour, minute, or second components of the duration (in absolute time).
2. Convert the resulting UTCDateTime back to LocalDateTime in the time zone that applies.
3. Subtract any week or day components of the duration from the date.
4. If the resulting time does not exist on the date due to a discontinuity in the time zone, use the semantics in Section 1.4.5 to convert to UTC and back to get a valid LocalDateTime.

1. The pointer MUST NOT reference inside an array (i.e., you MUST NOT insert/delete from an array; the array MUST be replaced in its entirety instead).
2. All parts prior to the last (i.e., the value after the final slash) MUST already exist on the object being patched.
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., alerts/1/offset and alerts.
4. The value for the patch MUST be valid for the property being set (of the correct type and obeying any other applicable restrictions), or, if null, the property MUST be optional.

• If null, remove the property from the patched object. If the key is not present in the parent, this a no-op.
• If non-null, set the value given as the value for this property (this may be a replacement or addition to the object being patched).

@type: String (mandatory)

This specifies the type of this object. This MUST be Relation.

relation: String[Boolean] (optional, default: empty Object)

This 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, specified in the property definition where the Relation object is used, a value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3):

first:

The linked object is the first in a series the linking object is part of.

next:

The linked object is 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 a subpart of the linked object.

The value for each key in the map MUST be true.

@type: String (mandatory)

This specifies the type of this object. This MUST be Link.

href: String (mandatory)

This is a URI [RFC 3986] from which the resource may be fetched.

This MAY be a data: URL [RFC 2397], but it is recommended that the file be hosted on a server to avoid embedding arbitrarily large data in JSCalendar object instances.

cid: String (optional)

This MUST be a valid content-id value according to the definition of Section 2 of RFC 2392. 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.

contentType: String (optional)

This is the media type [RFC 6838] of the resource, if known.

size: UnsignedInt (optional)

This is 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. Note that this is an informational estimate, and implementations must be prepared to handle the actual size being quite different when the resource is fetched.

rel: String (optional)

This identifies the relation of the linked resource to the object. If set, the value MUST be a relation type from the IANA "Link Relations" registry [LINKRELS], as established in [RFC 8288].

display: String (optional)

This describes the intended purpose of a link to an image. If set, the rel property MUST be set to icon. The value MUST be one of the following values, another value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3):

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

title: String (optional)

This is a human-readable, plain-text description of the resource.

• 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.
• 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 RFC 3986).

@type: String (mandatory)

This specifies the type of this object. This MUST be Location.

name: String (optional)

This is the human-readable name of the location.

description: String (optional)

This is the human-readable, plain-text instructions for accessing this location. This may be an address, set of directions, door access code, etc.

locationTypes: String[Boolean] (optional)

This is a set of one or more location types that describe this location. All types MUST be from the "Location Types Registry" [LOCATIONTYPES], as defined in [RFC 4589]. 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.

relativeTo: String (optional)

This 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 one of the following values, another value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3). Any value the client or server doesn't understand should be treated the same as if this property is omitted.

start:

The event/task described by this JSCalendar object occurs at this location at the time the event/task starts.

end:

The event/task described by this JSCalendar object occurs at this location at the time the event/task ends.

timeZone: TimeZoneId (optional)

This is a time zone for this location.

coordinates: String (optional)

This is a geo: URI [RFC 5870] for the location.

links: Id[Link] (optional)

This is a map of link ids to Link objects, representing external resources associated with this location, for example, a vCard or image. If there are no links, this MUST be omitted (rather than specified as an empty set).

@type: String (mandatory)

This specifies the type of this object. This MUST be VirtualLocation.

name: String (optional, default: empty String)

This is the human-readable name of the virtual location.

description: String (optional)

These are human-readable plain-text instructions for accessing this virtual location. This may be a conference access code, etc.

uri: String (mandatory)

This is a URI [RFC 3986] that represents how to connect to this virtual location.

This may be a telephone number (represented using the tel: scheme, e.g., tel:+1-555-555-5555) for a teleconference, a web address for online chat, or any custom URI.

features: String[Boolean] (optional)

A set of features supported by this virtual location. The set is represented as a map, with the keys being the feature. The value for each key in the map MUST be true.

The feature MUST be one of the following values, another value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3). Any value the client or server doesn't understand should be treated the same as if this feature is omitted.

audio:

Audio conferencing

chat:

Chat or instant messaging

feed:

Blog or atom feed

moderator:

Provides moderator-specific features

phone:

Phone conferencing

screen:

Screen sharing

video:

Video conferencing

1. The recurrenceRules property (Section 4.3.3) generates a set of extra date-times on which the object occurs.
2. The excludedRecurrenceRules property (Section 4.3.4) generates a set of date-times that are to be removed from the previously generated set of date-times on which the object occurs.
3. The recurrenceOverrides property (Section 4.3.5) defines date-times that are added or excluded to form the final set. (This property may also contain changes to the object to apply to particular instances.)

@type: String (mandatory)

This specifies the type of this object. This MUST be RecurrenceRule.

frequency: String (mandatory)

This is the time span covered by each iteration of this recurrence rule (see Section 4.3.3.1 for full semantics). This MUST be one of the following values:

• yearly
• monthly
• weekly
• daily
• hourly
• minutely
• secondly

This is the FREQ part from iCalendar, converted to lowercase.

interval: UnsignedInt (optional, default: 1)

This is 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.

rscale: String (optional, default: "gregorian")

This is the calendar system in which this recurrence rule operates, in lowercase. This MUST be either a CLDR-registered calendar system name [CLDR] or a vendor-specific value (see Section 3.3).

This is the RSCALE part from iCalendar [RFC 7529], converted to lowercase.

skip: String (optional, default: "omit")

This is the behavior 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:

• omit
• backward
• forward

This is the SKIP part from iCalendar [RFC 7529], converted to lowercase.

firstDayOfWeek: String (optional, default: "mo")

This is the day on which the week is considered to start, represented as a lowercase, abbreviated, and two-letter English day of the week. If included, it MUST be one of the following values:

• mo
• tu
• we
• th
• fr
• sa
• su

This is the WKST part from iCalendar.

byDay: NDay[] (optional)

These are days of the week on which to repeat. An NDay object has the following properties:

@type: String (mandatory)

This specifies the type of this object. This MUST be NDay.

day: String (mandatory)

This is a day of the week on which to repeat; the allowed values are the same as for the firstDayOfWeek recurrenceRule property.

This is the day of the week of the BYDAY part in iCalendar, 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 the nth-last occurrence within that period (i.e., -1 is the last occurrence, -2 the one before that, etc.).

This is the ordinal part of the BYDAY value in iCalendar (e.g., 1 or -3).

byMonthDay: Int[] (optional)

These are the 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.

byMonth: String[] (optional)

These are 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 calendar), with an optional "L" suffix (see [RFC 7529]) for leap 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.

byYearDay: Int[] (optional)

These are 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 1 to 366 and -366 to -1. Negative values offset from the end of the year. The array MUST have at least one entry if included.

This is the BYYEARDAY part from iCalendar.

byWeekNo: Int[] (optional)

These are the weeks of the year in which to repeat. Valid values are between 1 and the maximum number of weeks 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 1 to 53 and -53 to -1. The array MUST have at least one entry if included.

This is the BYWEEKNO part from iCalendar.

byHour: UnsignedInt[] (optional)

These are the hours of the day in which to repeat. Valid values are 0 to 23. The array MUST have at least one entry if included. This is the BYHOUR part from iCalendar.

byMinute: UnsignedInt[] (optional)

These are the minutes of the hour in which to repeat. Valid values are 0 to 59. The array MUST have at least one entry if included.

This is the BYMINUTE part from iCalendar.

bySecond: UnsignedInt[] (optional)

These are the seconds of the minute in which to repeat. Valid values are 0 to 60. The array MUST have at least one entry if included.

This is the BYSECOND part from iCalendar.

bySetPosition: Int[] (optional)

These are the occurrences within the recurrence interval to include in the final results. Negative values offset from the end of the list of occurrences. The array MUST have at least one entry if included. This is the BYSETPOS part from iCalendar.

count: UnsignedInt (optional)

These are the number of occurrences at which to range-bound the recurrence. This MUST NOT be included if an until property is specified.

This is the COUNT part from iCalendar.

until: LocalDateTime (optional)

These are the date-time at which to finish recurring. The last occurrence is on or before this date-time. This MUST NOT be included if a count property is specified. Note that if not specified otherwise for a specific JSCalendar object, this date is to be interpreted in the time zone specified in the JSCalendar object's timeZone property.

This is the UNTIL part from iCalendar.

A set of candidates is generated. This is every second within a period defined by the frequency property value:

yearly:

every second from midnight on the first day of a year (inclusive) to midnight the first day of the following year (exclusive).

If skip is not "omit", the calendar system has leap months, and there is a byMonth property, generate candidates for the leap months, even if they don't occur in this year.

If skip is not "omit" and there is a byMonthDay property, presume each month has the maximum number of days any month may have in this calendar system when generating candidates, even if it's more than this month actually has.

monthly:

every second from midnight on the first day of a month (inclusive) to midnight on the first of the following month (exclusive).

If skip is not "omit" and there is a byMonthDay property, presume the month has the maximum number of days any month may have in this calendar system when generating candidates, even if it's more than this month actually has.

weekly:

every second from midnight (inclusive) on the first day of the week (as defined by the firstDayOfWeek property or Monday if omitted) to midnight seven days later (exclusive).

daily:

every second from midnight at the start of the day (inclusive) to midnight at the end of the day (exclusive).

hourly:

every second from the beginning of the hour (inclusive) to the beginning of the next hour (exclusive).

minutely:

every second from the beginning of the minute (inclusive) to the beginning of the next minute (exclusive).

secondly:

only the second itself.

1. Each date-time candidate is compared against all of the byX properties of the rule except bySetPosition. If any property in the rule does not match the date-time, the date-time is eliminated. Each byX property is an array; the date-time matches the property if it matches any of the values in the array. The properties have the following semantics:

   byMonth:

   The date-time is in the given month.

   byWeekNo:

   The date-time is in the nth week of the year. Negative numbers mean the nth last week of the year. This corresponds to weeks according to week numbering, as defined in ISO.8601.2004, with a week defined as a seven-day period, starting on the firstDayOfWeek property value or Monday if omitted. Week number one of the calendar year is the first week that contains at least four days in that calendar year.

   If the date-time is not valid (this may happen when generating candidates with a skip property in effect), it is always eliminated by this property.

   byYearDay:

   The date-time is on the nth day of year. Negative numbers mean the nth last day of the year.

   If the date-time is not valid (this may happen when generating candidates with a skip property in effect), it is always eliminated by this property.

   byMonthDay:

   The date-time is on the given day of the month. Negative numbers mean the nth last day of the month.

   byDay:

   The date-time is on the given day of the week. If the day is prefixed by a number, it is the nth occurrence of that day of the week within the month (if frequency is monthly) or year (if frequency is yearly). Negative numbers mean the 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., February 31st 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 "forward") or decrement it (if skip is "backward") until a valid month is found, incrementing/decrementing the year as 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 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, February 30th and February 31st would both become the same "real" date, so one is eliminated as a duplicate.)
2. 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 indexed from the end of the list, with -1 being the last item, -2 the second from last, etc.
3. Any date-times before the start date of the event are eliminated (see below for why this might be needed).
4. 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 is "omit".)
5. 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.

1. The initial date-time to which the rule is applied (the start date-time for events or the start or due date-time for tasks) is always the first occurrence in the expansion (and is counted if the recurrence is limited by a count property), even if it would normally not match the rule.
2. The first set of candidates to consider is that which would contain the initial date-time. This means the first set may include candidates before the initial date-time; such candidates are eliminated from the results in step 4 of the list above.
3. The following properties MUST be implicitly added to the rule under the given conditions:
   • If frequency is not secondly and there is no bySecond property, add a bySecond property with the sole value being the seconds value of the initial date-time.
   • If frequency is not secondly or minutely and there is no byMinute property, add a byMinute property with the sole value being the minutes value of the initial date-time.
   • If frequency is not secondly, minutely, or hourly and there is no byHour property, add a byHour property with the sole value being the hours value of the initial date-time.
   • If frequency is weekly and there is no byDay property, add a byDay property with the sole value being the day of the week of the initial date-time.
   • If frequency is monthly and there is no byDay property and no byMonthDay property, add a byMonthDay property with the sole value being the day of the month of the initial date-time.
   • If frequency is yearly and there is no byYearDay property:
     • If there are no byMonth or byWeekNo properties, and either there is a byMonthDay property or there is no byDay property, add a byMonth property with the sole value being the month of the initial date-time.
     • If there are no byMonthDay, byWeekNo, or byDay properties, add a byMonthDay property with the sole value being the day of the month of the initial date-time.
     • If there is a byWeekNo property and no byMonthDay or byDay properties, add a byDay property with the sole value being the day of the week of the initial date-time.

• @type
• excludedRecurrenceRules
• method
• privacy
• prodId
• recurrenceId
• recurrenceIdTimeZone
• recurrenceOverrides
• recurrenceRules
• relatedTo
• replyTo
• sentBy
• timeZones
• uid

free:

The object should be ignored when calculating whether the user is busy.

busy:

The object should be included when calculating whether the user is busy.

public:

The full details of the object are visible to those whom the object's calendar is shared with.

private:

The details of the object are hidden; only the basic time and metadata are shared. The following properties MAY be shared; any other properties MUST NOT be shared:

• @type
• created
• due
• duration
• estimatedDuration
• freeBusyStatus
• privacy
• recurrenceOverrides (Only patches that apply to another permissible property are allowed to be shared.)
• sequence
• showWithoutTime
• start
• timeZone
• timeZones
• uid
• updated

secret:

The object is hidden completely (as though it did not exist) when the calendar this object is in is shared.

imip:

The organizer accepts an iCalendar Message-Based Interoperability Protocol (iMIP) [RFC 6047] response at this email address. The value MUST be a mailto: URI.

web:

Opening this URI in a web browser will provide the user with a page where they can submit a reply to the organizer. The value MUST be a URL using the https: scheme.

other:

The organizer is identified by this URI, but the method for submitting the response is undefined.

@type: String (mandatory)

This specifies the type of this object. This MUST be Participant.

name: String (optional)

This is the display name of the participant (e.g., "Joe Bloggs").

email: String (optional)

This is the email address to use to contact the participant or, for example, match with an address book entry. If set, the value MUST be a valid addr-spec value as defined in Section 3.4.1 of [RFC 5322].

description: String (optional)

This is a plain-text description of this participant. For example, this may include more information about their role in the event or how best to contact them.

sendTo: String[String] (optional)

This 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 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 [RFC 6047] 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 for submitting the invitation is undefined.

kind: String (optional)

This is what kind of entity this participant is, if known.

This MUST be one of the following values, another value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3). 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 other than a location, such as a projector

roles: String[Boolean] (mandatory)

This is 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 one of the following values, another value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3):

owner:

The participant is an owner of the object. This signifies they have permission to make changes to it that affect the other participants. Nonowner participants may only change properties that affect only themselves (for example, setting their own alerts or changing their RSVP status).

attendee:

The participant is expected to be present at the event.

optional:

The participant's involvement with the event is optional. This is expected to be primarily combined with the "attendee" role.

informational:

The participant is copied for informational reasons and is not expected to attend.

chair:

The participant is in charge of the event/task when it occurs.

contact:

The participant is someone that may be contacted for information about the event.

The value for each key in the map MUST be true. It is expected that no more than one of the roles "attendee" and "informational" be present; if more than one are given, "attendee" takes precedence over "informational". Roles that are unknown to the implementation MUST be preserved.

locationId: Id (optional)

This is 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.

language: String (optional)

This is the language tag, as defined in [RFC 5646], that best describes the participant's preferred language, if known.

participationStatus: String (optional, default: needs-action)

This is the participation status, if any, of this participant.

The value MUST be one of the following values, another value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3):

needs-action:

No status has yet been 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 attendance to another participant, as specified in the delegatedTo property.

participationComment: String (optional)

This is a note from the participant to explain their participation status.

expectReply: Boolean (optional, default: false)

If true, the organizer is expecting the participant to notify them of their participation status.

scheduleAgent: String (optional, default: server)

This is who is responsible for sending scheduling messages with this calendar object to the participant.

The value MUST be one of the following values, another value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3):

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.

scheduleForceSend: Boolean (optional, default: false)

A client may set the property on a participant to true to request that the server send a scheduling message to the participant when it would not normally do so (e.g., if no significant change is made the object or the scheduleAgent is set to client). The property MUST NOT be stored in the JSCalendar object on the server or appear in a scheduling message.

scheduleSequence: UnsignedInt (optional, default: 0)

This is the sequence number of the last response from the participant. If defined, this MUST be a nonnegative integer.

This can be used to determine whether the participant has sent a new response following significant changes to the calendar object and to determine if future responses are responding to a current or older view of the data.

scheduleStatus: String[] (optional)

This is a list of status codes, returned from the processing of the most recent scheduling message sent to this participant. The status codes MUST be valid statcode values as defined in the ABNF in Section 3.8.8.3 of RFC 5545.

Servers MUST only add or change this property when they send a scheduling message to the participant. Clients SHOULD NOT change or remove this property if it was provided by the server. Clients MAY add, change, or remove the property for participants where the client is handling the scheduling.

This property MUST NOT be included in scheduling messages.

scheduleUpdated: UTCDateTime (optional)

This is the timestamp for the most recent response from this participant.

This is the updated property of the last response when using iTIP. It can be compared to the updated property in future responses to detect and discard older responses delivered out of order.

sentBy: String (optional)

This is the email address in the "From" header of the email that last updated this participant via iMIP. This SHOULD only be set if the email address is different to that in the mailto URI of this participant's imip method in the sendTo property (i.e., the response was received from a different address to that which the invitation was sent to). If set, the value MUST be a valid addr-spec value as defined in Section 3.4.1 of [RFC 5322].

invitedBy: Id (optional)

This is the id of the participant who added this participant to the event/task, if known.

delegatedTo: Id[Boolean] (optional)

This is 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 map MUST be true. If there are no delegates, this MUST be omitted (rather than specified as an empty set).

delegatedFrom: Id[Boolean] (optional)

This is 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 map MUST be true. If there are no delegators, this MUST be omitted (rather than specified as an empty set).

memberOf: Id[Boolean] (optional)

This is a set of group participants that were invited to this calendar object, which caused this participant to be invited due to their membership in the group(s). Each key in the set MUST be the id of a participant. The value for each key in the map MUST be true. If there are no groups, this MUST be omitted (rather than specified as an empty set).

links: Id[Link] (optional)

This is a map of link ids to Link objects, representing external resources associated with this participant, for example, a vCard or image. If there are no links, this MUST be omitted (rather than specified as an empty set).

progress: String (optional; only allowed for participants of a Task)

This represents the progress of the participant for this task. It MUST NOT be set if the participationStatus of this participant is any value other than accepted. See Section 5.2.5 for allowed values and semantics.

progressUpdated: UTCDateTime (optional; only allowed for participants of a Task)

This specifies the date-time the progress property was last set on this participant. See Section 5.2.6 for allowed values and semantics.

percentComplete: UnsignedInt (optional; only allowed for participants of a Task)

This represents the percent completion of the participant for this task. The property value MUST be a positive integer between 0 and 100.

@type: String (mandatory)

This specifies the type of this object. This MUST be Alert.

trigger: OffsetTrigger|AbsoluteTrigger|UnknownTrigger (mandatory)

This defines when to trigger the alert. New types may be defined in future documents.

An OffsetTrigger object has the following properties:

@type: String (mandatory)

This specifies the type of this object. This MUST be OffsetTrigger.

offset: SignedDuration (mandatory)

This defines the offset at which to trigger the alert relative to the time property defined in the relativeTo property of the alert. Negative durations signify alerts before the time property; positive durations signify alerts after the time property.

relativeTo: String (optional, default: start)

This specifies the time property that the alert offset is relative to. The value MUST be one of the following:

start:

triggers the alert relative to the start of the calendar object

end:

triggers the alert relative to the end/due time of the calendar object

An AbsoluteTrigger object has the following properties:

@type: String (mandatory)

This specifies the type of this object. This MUST be AbsoluteTrigger.

when: UTCDateTime (mandatory)

This defines a specific UTC date-time when the alert is triggered.

An UnknownTrigger object is an object that contains an @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 specifications. Implementations SHOULD NOT trigger for trigger types they do not understand but MUST preserve them.

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, setting the acknowledged property MUST NOT add a new override to the recurrenceOverrides property. If the alert is not already overridden, the acknowledged property MUST be set on the alert in the base event/task.

Certain kinds of alert action may not provide feedback as to when the user sees them, for example, email-based alerts. For those kinds of alerts, this property MUST be set immediately when the alert is triggered and the action is successfully carried out.

relatedTo: String[Relation] (optional)

This relates this alert to other alerts in the same JSCalendar object. If the user wishes to snooze an alert, the application MUST create an alert to trigger after snoozing. This new snooze alert MUST set a parent relation to the identifier of the original alert.

action: String (optional, default: display)

This describes how to alert the user.

The value MUST be at most one of the following values, a value registered in the IANA "JSCalendar Enum Values" registry, or a vendor-specific value (see Section 3.3):

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 them of the alert. This action is typically only appropriate for server implementations.

• title
• description
• name

• To avoid conflict with names in the IANA Time Zone Database [TZDB], it MUST start with the / character.
• It MUST be a valid paramtext value, as specified in Section 3.1 of RFC 5545.
• At least one other property in the same JSCalendar object MUST reference a time zone using this identifier (i.e., orphaned time zones are not allowed).

@type: String (mandatory)

This specifies the type of this object. This MUST be TimeZone.

tzId: String (mandatory)

This is the TZID property from iCalendar. Note that this implies that the value MUST be a valid paramtext value as specified in Section 3.1. of [RFC 5545].

updated: UTCDateTime (optional)

This is the LAST-MODIFIED property from iCalendar.

url: String (optional)

This is the TZURL property from iCalendar.

validUntil: UTCDateTime (optional)

This is the TZUNTIL property from iCalendar, specified in [RFC 7808].

aliases: String[Boolean] (optional)

This maps the TZID-ALIAS-OF properties from iCalendar, specified in [RFC 7808], to a JSON set of aliases. The set is represented as an object, with the keys being the aliases. The value for each key in the map MUST be true.

standard: TimeZoneRule[] (optional)

This the STANDARD sub-components from iCalendar. The order MUST be preserved during conversion.

daylight: TimeZoneRule[] (optional)

This the DAYLIGHT sub-components from iCalendar. The order MUST be preserved during conversion.

@type: String (mandatory)

This specifies the type of this object. This MUST be TimeZoneRule.

start: LocalDateTime (mandatory)

This is the DTSTART property from iCalendar.

offsetFrom: String (mandatory)

This is the TZOFFSETFROM property from iCalendar.

offsetTo: String (mandatory)

This is the TZOFFSETTO property from iCalendar.

recurrenceRules: RecurrenceRule[] (optional)

This is the RRULE property mapped, as specified in Section 4.3.3. During recurrence rule evaluation, the until property value MUST be interpreted as a local time in the UTC time zone.

recurrenceOverrides: LocalDateTime[PatchObject] (optional)

This maps the RDATE properties from iCalendar. The set is represented as an object, with the keys being the recurrence dates. The patch object MUST be the empty JSON object ({}).

names: String[Boolean] optional)

This maps the TZNAME properties from iCalendar to a JSON set. The set is represented as an object, with the keys being the names, excluding any tznparam component from iCalendar. The value for each key in the map MUST be true.

comments: String[] (optional)

This maps the COMMENT properties from iCalendar. The order MUST be preserved during conversion.

confirmed:

indicates the event is definitely happening

cancelled:

indicates the event has been cancelled

tentative:

indicates the event may happen

completed:

if the progress property value of all participants is completed

failed:

if at least one progress property value of a participant is failed

in-process:

if at least one progress property value of a participant is in-process

needs-action:

if none of the other criteria match

needs-action:

indicates the task needs action

in-process:

indicates the task is in process

completed:

indicates the task is completed

failed:

indicates the task failed

cancelled:

indicates the task was cancelled

• @type
• uid
• prodId
• created
• updated
• title
• description
• descriptionContentType
• links
• locale
• keywords
• categories
• color
• timeZones

Type name:

application

Subtype name:

jscalendar+json

Required parameters:

type

The type parameter conveys the type of the JSCalendar data in the body part. The allowed parameter values correspond to the @type property of the JSON-formatted JSCalendar object in the body:

event:

The @type property value MUST be Event.

task:

The @type property value MUST be Task.

group:

The @type property value MUST be Group.

No other parameter values are allowed. The parameter MUST NOT occur more than once.

Optional parameters:

none

Encoding considerations:

This is the same as the encoding considerations of application/json, as specified in Section 11 of RFC 8259.

Security considerations:

See Section 7 of this document.

Interoperability considerations:

While JSCalendar is designed to avoid ambiguities as much as possible, when converting objects from other calendar formats to/from JSCalendar, it is possible that differing representations for the same logical data or ambiguities in interpretation might arise. The semantic equivalence of two JSCalendar objects may be determined differently by different applications, for example, where URL values differ in case between the two objects.

Published specification:

RFC 8984

Applications that use this media type:

Applications that currently make use of the text/calendar and application/calendar+json media types can use this as an alternative. Similarly, applications that use the application/json media type to transfer calendaring data can use this to further specify the content.

Fragment identifier considerations:

A JSON Pointer fragment identifier may be used, as defined in RFC 6901, Section 6.

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:

calsify@ietf.org

Intended usage:

COMMON

Restrictions on usage:

N/A

Author:

See the "Author's Address" section of this document.

Change controller:

IETF

Property Name:

This is the name of the property. The property name MUST 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; however, the same name SHOULD only be used when the semantics are analogous.

Property Type:

This is the type of this property, using type signatures, as specified in Section 1.3. The property type MUST be registered in the "JSCalendar Types" registry.

Property Context:

This is a comma-separated list of JSCalendar object types this property is allowed on.

Reference or Description:

This is a brief description or RFC number and section reference where the property is specified (omitted for "reserved" property names).

Intended Usage:

This may be "common", "reserved", or "obsolete".

Change Controller:

This is who may request a change to this entry's definition (IETF for RFCs from the IETF stream).

Type Name:

the name of the type

Reference or Description:

a brief description or RFC number and section reference where the Type is specified (may be omitted for "reserved" type names)

Intended Use:

common, reserved, or obsolete

Change Controller:

who may request a change to this entry's definition (IETF for RFCs from the IETF stream)

Property Name:

These are the name(s) of the property or properties where these values may be used. This MUST be registered in the "JSCalendar Properties" registry.

Context:

This is the list of allowed object types where the property or properties may appear, as registered in the "JSCalendar Properties" registry. This disambiguates where there may be two distinct properties with the same name in different contexts.

Change Controller:

(IETF for properties defined in RFCs from the IETF stream).

Initial Contents:

This is the initial list of defined values for this enum, using the template defined in Section 8.4.2. A subregistry will be created with these values for this property name/context tuple.

Enum Value:

the verbatim value of the enum

Reference or Description:

a brief description or RFC number and section reference for the semantics of this value

Property Name:

action

Context:

Alert

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
display	Section 4.5.2
email	Section 4.5.2

Table 3: JSCalendar Enum Values for action (Context: Alert)

Property Name:

display

Context:

Link

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
badge	Section 1.4.11
graphic	Section 1.4.11
fullsize	Section 1.4.11
thumbnail	Section 1.4.11

Table 4: JSCalendar Enum Values for display (Context: Link)

Property Name:

features

Context:

VirtualLocation

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
audio	Section 4.2.6
chat	Section 4.2.6
feed	Section 4.2.6
moderator	Section 4.2.6
phone	Section 4.2.6
screen	Section 4.2.6
video	Section 4.2.6

Table 5: JSCalendar Enum Values for features (Context: VirtualLocation)

Property Name:

freeBusyStatus

Context:

Event, Task

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
free	Section 4.4.2
busy	Section 4.4.2

Table 6: JSCalendar Enum Values for freeBusyStatus (Context: Event, Task)

Property Name:

kind

Context:

Participant

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
individual	Section 4.4.6
group	Section 4.4.6
resource	Section 4.4.6
location	Section 4.4.6

Table 7: JSCalendar Enum Values for kind (Context: Participant)

Property Name:

participationStatus

Context:

Participant

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
needs-action	Section 4.4.6
accepted	Section 4.4.6
declined	Section 4.4.6
tentative	Section 4.4.6
delegated	Section 4.4.6

Table 8: JSCalendar Enum Values for participationStatus (Context: Participant)

Property Name:

privacy

Context:

Event, Task

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
public	Section 4.4.3
private	Section 4.4.3
secret	Section 4.4.3

Table 9: JSCalendar Enum Values for privacy (Context: Event, Task)

Property Name:

progress

Context:

Task, Participant

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
needs-action	Section 5.2.5
in-process	Section 5.2.5
completed	Section 5.2.5
failed	Section 5.2.5
cancelled	Section 5.2.5

Table 10: JSCalendar Enum Values for progress (Context: Task, Participant)

Property Name:

relation

Context:

Relation

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
first	Section 1.4.10
next	Section 1.4.10
child	Section 1.4.10
parent	Section 1.4.10

Table 11: JSCalendar Enum Values for relation (Context: Relation)

Property Name:

relativeTo

Context:

OffsetTrigger, Location

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
start	Section 4.5.2
end	Section 4.5.2

Table 12: JSCalendar Enum Values for relativeTo (Context: OffsetTrigger, Location)

Property Name:

roles

Context:

Participant

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
owner	Section 4.4.6
attendee	Section 4.4.6
optional	Section 4.4.6
informational	Section 4.4.6
chair	Section 4.4.6
contact	Section 4.4.6

Table 13: JSCalendar Enum Values for roles (Context: Participant)

Property Name:

scheduleAgent

Context:

Participant

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
server	Section 4.4.6
client	Section 4.4.6
none	Section 4.4.6

Table 14: JSCalendar Enum Values for scheduleAgent (Context: Participant)

Property Name:

status

Context:

Event

Change Controller:

IETF

Initial Contents:

Enum Value	Reference or Description
confirmed	Section 5.1.3
cancelled	Section 5.1.3
tentative	Section 5.1.3

Table 15: JSCalendar Enum Values for status (Context: Event)

[CLDR]

"Unicode Common Locale Data Repository",
<http://cldr.unicode.org/>.

[COLORS]

T Çelik, C Lilley, and L Baron, "CSS Color Module Level 3", June 2018,
<https://www.w3.org/TR/css-color-3/>.

[RFC2119]

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

[RFC2392]

E. Levinson, "Content-ID and Message-ID Uniform Resource Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998,
<https://www.rfc-editor.org/info/rfc2392>.

[RFC2397]

L. Masinter, "The "data" URL scheme", RFC 2397, DOI 10.17487/RFC2397, August 1998,
<https://www.rfc-editor.org/info/rfc2397>.

[RFC3339]

G. Klyne, and C. Newman, "Date and Time on the Internet: Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.

[RFC3986]

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

[RFC4122]

P. Leach, M. Mealling, and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>.

[RFC4589]

H. Schulzrinne, and H. Tschofenig, "Location Types Registry", RFC 4589, DOI 10.17487/RFC4589, July 2006,
<https://www.rfc-editor.org/info/rfc4589>.

[RFC4648]

S. Josefsson, "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>.

[RFC5234]

D. Crocker, and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.

[RFC5322]

P. Resnick, "Internet Message Format", RFC 5322, DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.

[RFC5545]

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

[RFC5546]

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

[RFC5646]

A. Phillips, and M. Davis, "Tags for Identifying Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, September 2009,
<https://www.rfc-editor.org/info/rfc5646>.

[RFC5870]

A. Mayrhofer, and C. Spanring, "A Uniform Resource Identifier for Geographic Locations ('geo' URI)", RFC 5870, DOI 10.17487/RFC5870, June 2010,
<https://www.rfc-editor.org/info/rfc5870>.

[RFC6047]

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

[RFC6838]

N. Freed, J. Klensin, and T. Hansen, "Media Type Specifications and Registration Procedures", BCP 13, RFC 6838, DOI 10.17487/RFC6838, January 2013,
<https://www.rfc-editor.org/info/rfc6838>.

[RFC6901]

P. Bryan, K. Zyp, and M. Nottingham, "JavaScript Object Notation (JSON) Pointer", RFC 6901, DOI 10.17487/RFC6901, April 2013,
<https://www.rfc-editor.org/info/rfc6901>.

[RFC7493]

T. Bray, "The I-JSON Message Format", RFC 7493, DOI 10.17487/RFC7493, March 2015,
<https://www.rfc-editor.org/info/rfc7493>.

[RFC7529]

C. Daboo, 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,
<https://www.rfc-editor.org/info/rfc7529>.

[RFC7808]

M. Douglass, and C. Daboo, "Time Zone Data Distribution Service", RFC 7808, DOI 10.17487/RFC7808, March 2016,
<https://www.rfc-editor.org/info/rfc7808>.

[RFC8126]

M. Cotton, B. Leiba, and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.

[RFC8174]

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

[RFC8259]

T. Bray, "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.

[RFC8288]

M. Nottingham, "Web Linking", RFC 8288, DOI 10.17487/RFC8288, October 2017,
<https://www.rfc-editor.org/info/rfc8288>.

[TZDB]

IANA, "Time Zone Database",
<https://www.iana.org/time-zones>.

[ISO.9070.1991]

ISO/IEC, "Information technology -- SGML support facilities -- Registration procedures for public text owner identifiers", ISO/IEC 9070:1991, April 1991,
<https://www.iso.org/standard/16645.html>.

[LINKRELS]

IANA, "Link Relations: Link Relation Types",
<https://www.iana.org/assignments/link-relations>.

[LOCATIONTYPES]

IANA, "Location Types Registry",
<https://www.iana.org/assignments/location-type-registry>.

[MEDIATYPES]

IANA, "Media Types",
<https://www.iana.org/assignments/media-types>.

[RFC6376]

D. Crocker, T. Hansen, and M. Kucherawy, "DomainKeys Identified Mail (DKIM) Signatures", STD 76, RFC 6376, DOI 10.17487/RFC6376, September 2011,
<https://www.rfc-editor.org/info/rfc6376>.

[RFC7265]

P. Kewisch, C. Daboo, and M. Douglass, "jCal: The JSON Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May 2014,
<https://www.rfc-editor.org/info/rfc7265>.

[RFC7986]

C. Daboo, "New Properties for iCalendar", RFC 7986, DOI 10.17487/RFC7986, October 2016,
<https://www.rfc-editor.org/info/rfc7986>.

Neil Jenkins

Robert Stepanek