Re: DTSTART for recurrence instances

On 10 déc. 03, at 02:33, Doug Royer wrote:
> (Again the topic is DTSTART for recurrence instances, not any thing 
> else)
> Is there any disagreement that these are -also- a valid ways to change 
> the 2nd instance:
> [...]
> Method A:  Now later ORGANIZER sends iTIP updates to move the second 
> instance
> from  noon->1pm  and have it at 2pm->3:30pm:
>
>   BEGIN:VCALENDAR
>   ...
>   METHOD:REQUEST
>   BEGIN:VEVENT
>   UID:XXX
>   SEQUENCE:1
>   ...
>   DTSTART: 1-dec-2003 at noon
>   DTEND: 1-dec-2003 at 1pm
>   ...
>   RDATE:3-dec-2003 at noon
>   ...
>   END:VEVENT
>   END:VCALENDAR
>
>   BEGIN:VCALENDAR
>   METHOD:ADD
>   BEGIN:VEVENT
>   UID:XXX
>   SEQUENCE:2
>   ...
>   DTSTART:2-dec-2003 at 2pm
>   DTEND:2-dec-2003 at 3:30pm
>   ...
>   END:VEVENT
>   END:VCALENDAR

Method A: I agree. I rephrase to be sure we all understand it the same 
way:
	- a REQUEST to  modify the event by having an instance on at 3-dec 
noon, the other one being the DTSTART at 1-dec-2003 noon
	- an ADD to then add another instance at 2-dec-2003 2pm

>  Method B:  Now later ORGANIZER sends iTIP updates to move the second 
> instance
> from  noon->1pm  and have it at 2pm->3:30pm:
>
>   BEGIN:VEVENT
>   UID:XXX
>   SEQUENCE:1
>   ...
>   METHOD:REQUEST
>   ATTENDEE:attendee
>   ...
>   DTSTART: 1-dec-2003 at noon
>   DTEND: 1-dec-2003 at 1pm
>   ...
>   RRULE:FREQ=DAILY;COUNT=3
>   EXDATE:2-dec-2003 at noon
>   ...
>   END:VEVENT
>
>   BEGIN:VCALENDAR
>   METHOD:ADD
>   BEGIN:VEVENT
>   UID:XXX
>   SEQUENCE:2
>   ...
>   DTSTART:2-dec-2003 at 2pm
>   DTEND:2-dec-2003 at 3:30pm
>   ...
>   END:VEVENT
>   END:VCALENDAR

Method B: I agree
	- a REQUEST to modify the event. We keep the RRULE and remove the 
2-dec noon instance
	- a subsequent ADD to add the 2-dec-2003 2pm instance

>  Method C:  -OR- this:
>
>   BEGIN:VCALENDAR
>   ...
>   METHOD:CANCEL
>   BEGIN:VEVENT
>   UID:XXX
>   SEQUENCE:1
>   ...
>   RECURRENCE-ID:2-dec-2003 at noon
>   ...
>   END:VEVENT
>   END:VCALENDAR
>
>   BEGIN:VCALENDAR
>   METHOD:ADD
>   BEGIN:VEVENT
>   UID:XXX
>   SEQUENCE:2
>   ...
>   DTSTART:2-dec-2003 at 2pm
>   DTEND:2-dec-2003 at 3:30pm
>   ...
>   END:VEVENT
>   END:VCALENDAR
>
> Do you agree that these are also valid objects to tell the ATTENDEE of 
> the single instance change?

Method C: ok too
	- CANCEL to remove the instance identified by UID  + recurrence-ID 
2-dec-noon
	- then a ADD to put another instance at 2-dec-2003 2pm
And in all cases (A,B,C,D), SEQUENCE for all instances is 2.
I also agree with Michael's comments that we end with a calendar where 
we have 1-dec noon->1pm, 2-dec 2pm->3:30pm, 3-dec noon->1pm and I'm not 
sure I can consider every method as a 'reschedule'.

Ol.