Cancel 1 instance of a repeating date in iCalendar

Question

I have repeating event in October 2013.

I need to cancel 1 instance in October 15.

How it can be done? Special tags? Calendar is listed below:

BEGIN:VCALENDAR
PRODID:-//atomos.pro//test//ru
VERSION:2.0

BEGIN:VEVENT
DTSTART;TZID=Europe/Moscow:20131001T100000Z
DTEND;TZID=Europe/Moscow:20131001T110000Z
RRULE:FREQ=DAILY;UNTIL=20131031T120000Z
SUMMARY:NEED
LOCATION:TEST
END:VEVENT

END:VCALENDAR

Answer 1

Are you talking about sending a CANCEL to the attendee of the meeting or about just excluding the 15th of October date ? Don't see any attendee in there but I imagine that you did not include all properties in your sample (UID is missing as well)

For the former you would send an iTIP CANCEL to all the attendees with a RECURRENCE-ID matching the DTSTART of the instance for the 15th of October (see https://www.rfc-editor.org/rfc/rfc5546#section-3.2.5). So something like:

BEGIN:VCALENDAR
PRODID:-//atomos.pro//test//ru
VERSION:2.0
METHOD:CANCEL
BEGIN:VEVENT
UID:(same UID as the original VEVENT)
RECURRENCE-ID;TZID=Europe/Moscow:20131015T100000Z
DTSTART;TZID=Europe/Moscow:20131001T100000Z
DTEND;TZID=Europe/Moscow:20131001T110000Z
STATUS:CANCELLED
SUMMARY:NEED
LOCATION:TEST
END:VEVENT
END:VCALENDAR

If it is the later, you can simply add an EXDATE for the 15th of October to your event, i.e.:

BEGIN:VEVENT
DTSTART;TZID=Europe/Moscow:20131001T100000Z
DTEND;TZID=Europe/Moscow:20131001T110000Z
RRULE:FREQ=DAILY;UNTIL=20131031T120000Z
EXDATE;TZID=Europe/Moscow:20131015T100000Z
SUMMARY:NEED
LOCATION:TEST
END:VEVENT

Answer 2

arnaudq, thank you. this example hides events for 15 and 20 october.

BEGIN:VCALENDAR
PRODID:-//atomos.pro//test//ru
VERSION:2.0

BEGIN:VEVENT
DTSTART;TZID=Europe/Moscow:20131001T100000Z
DTEND;TZID=Europe/Moscow:20131001T110000Z
RRULE:FREQ=DAILY;UNTIL=20131031T120000Z
EXDATE;TZID=Europe/Moscow:20131015T100000Z,20131020T100000Z
SUMMARY:WORKING
LOCATION:NOW
END:VEVENT

END:VCALENDAR