2.2.151 [RFC5546] Section 5.2.2 Unexpected Reply from an Unknown Delegate

V0315:

The specification states that when an attendee delegates an item to another calendar user they MUST send a REPLY method to the organizer using the ATTENDEE properties to indicate that the request was delegated and to whom.

Microsoft Office Outlook 2007, Microsoft Outlook 2010, Microsoft Outlook 2013, Microsoft Outlook 2016, Microsoft Outlook 2019

Outlook does not permit attendees to delegate invitations to another calendar user. Outlook ignores DELEGATED-TO and DELEGATED-FROM parameters on import.

V0316:

The specification states that it is possible for an organizer to receive a REPLY from a calendar user not listed as one of the original attendees. The resolution is left to the implementation but it is expected that the calendaring software will either accept the reply or hold it until the related REPLY is received from the delegator.

Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019

Outlook allows calendar users not on the original attendee list to send REPLY-type iCalendar objects in response to a forwarded meeting request.

On import, Outlook ignores the DELEGATED-TO and DELEGATED-FROM parameters. Outlook can import REPLY-type iCalendar objects from uninvited calendar users. However, responses from uninvited calendar users are not tracked in the meeting.

V0317:

The specification states that if the version of the REPLY method is out of date the organizer SHOULD treat the message as a REFRESH message and update the delegate with the correct version.

Office Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016, Outlook 2019

Outlook permits organizers to add attendees and send out meeting updates. This is not done automatically for the organizer.

Outlook can import and render out-of-date responses, but they are not tracked in the meeting.