Property Name
RECURRENCE-ID
Purpose
This property is used in conjunction with the "UID" and "SEQUENCE" properties to identify a specific instance of a recurring "VEVENT", "VTODO", or "VJOURNAL" calendar component. The property value is the original value of the "DTSTART" property of the recurrence instance. Value Type: The default value type is DATE-TIME. The value type can be set to a DATE value type. This property MUST have the same value type as the "DTSTART" property contained within the recurring component. Furthermore, this property MUST be specified as a date with local time if and only if the "DTSTART" property contained within the recurring component is specified as a date with local time.
Property Parameters
IANA, non-standard, value data type, time zone identifier, and recurrence identifier range parameters can be specified on this property.
Conformance
This property can be specified in an iCalendar object containing a recurring calendar component.
Description
The full range of calendar components specified by a recurrence set is referenced by referring to just the "UID" property value corresponding to the calendar component. The "RECURRENCE-ID" property allows the reference to an individual instance within the recurrence set.
If the value of the "DTSTART" property is a DATE type value, then the value MUST be the calendar date for the recurrence instance.
The DATE-TIME value is set to the time when the original recurrence instance would occur; meaning that if the intent is to change a Friday meeting to Thursday, the DATE-TIME is still set to the original Friday meeting.
The "RECURRENCE-ID" property is used in conjunction with the "UID" and "SEQUENCE" properties to identify a particular instance of a recurring event, to-do, or journal. For a given pair of "UID" and "SEQUENCE" property values, the "RECURRENCE-ID" value for a recurrence instance is fixed.
The "RANGE" parameter is used to specify the effective range of recurrence instances from the instance specified by the "RECURRENCE-ID" property value. The value for the range parameter can only be "THISANDFUTURE" to indicate a range defined by the given recurrence instance and all subsequent instances. Subsequent instances are determined by their "RECURRENCE-ID" value and not their current scheduled start time. Subsequent instances defined in separate components are not impacted by the given recurrence instance. When the given recurrence instance is rescheduled, all subsequent instances are also rescheduled by the same time difference. For instance, if the given recurrence instance is rescheduled to start 2 hours later, then all subsequent instances are also rescheduled 2 hours later. Similarly, if the duration of the given recurrence instance is modified, then all subsequence instances are also modified to have this same duration.
Note: The "RANGE" parameter may not be appropriate to reschedule specific subsequent instances of complex recurring calendar component. Assuming an unbounded recurring calendar component scheduled to occur on Mondays and Wednesdays, the "RANGE" parameter could not be used to reschedule only the future Monday instances to occur on Tuesday instead. In such cases, the calendar application could simply truncate the unbounded recurring calendar component (i.e., with the "COUNT" or "UNTIL" rule parts), and create two new unbounded recurring calendar components for the future instances.
Format Definition
This property is defined by the following notation:
recurid = "RECURRENCE-ID" ridparam ":" ridval CRLF
ridparam = *(
;
; The following are OPTIONAL,
; but MUST NOT occur more than once.
;
(";" "VALUE" "=" ("DATE-TIME" / "DATE")) /
(";" tzidparam) / (";" rangeparam) /
;
; The following is OPTIONAL,
; and MAY occur more than once.
;
(";" other-param)
;
)
ridval = date-time / date ;Value MUST match value type
Example
The following are examples of this property
RECURRENCE-ID;VALUE=DATE:19960401
RECURRENCE-ID;RANGE=THISANDFUTURE:19960120T120000Z