ICalendar and event updates not working in Outlook

Tom Carter picture Tom Carter · Sep 5, 2008 · Viewed 25.7k times · Source

I'm generating ICalendar (.ics) files.

Using the UID and SEQUENCE fields I can update existing events in Google Calendar and in Windows Calendar BUT NOT in MS Outlook 2007 - it just creates a second event

How do I get them to work for Outlook ?

Thanks

Tom

Answer

Tom Carter picture Tom Carter · Sep 5, 2008

I've continued to do some testing and have now managed to get Outlook to update and cancel events based on the .cs file.

Outlook in fact seems to respond to the rules defined in RFC 2446

In summary you have to specify

METHOD:REQUEST and ORGANIZER:xxxxxxxx

in addition to UID: and SEQUENCE:

For a cancellation you have to specify METHOD:CANCEL

Request/Update Example

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//SYFADIS//PORTAIL FORMATION//FR
METHOD:REQUEST
BEGIN:VEVENT
UID:[email protected]
SEQUENCE:5
DTSTAMP:20081106T154911Z
ORGANIZER:[email protected]
DTSTART:20081113T164907
DTEND:20081115T170000
SUMMARY:TestTraining
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR

Cancel Example;

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//SYFADIS//PORTAIL FORMATION//FR
METHOD:CANCEL
BEGIN:VEVENT
UID:[email protected]
SEQUENCE:7
DTSTAMP:20081106T154916Z
ORGANIZER:[email protected]
DTSTART:20081113T164907
SUMMARY:TestTraining
STATUS:CANCELLED
END:VEVENT
END:VCALENDAR