Known CalDAV Issues

This is a set of issues that are indirectly related to CalDAV; they are interoperability issues that manifest in CalDAV but their root cause is in Axigen's implementation.

• Axigen does not implement support for schedule status values 

  • RFC 6638 describes a mechanism that allows a CalDAV client to know the status of the iTIP delivery for a given attendee.

  • E.g. If the organizer makes a mistake when filling in the address of the attendee in the current implementation he/she can notice this mistake when he/she receives the NDR (non delivery report) for the iTIP message. If Axigen would implement schedule status values the CalDAV client would be informed of a delivery failure in the VCALENDAR item.

• Notifications belonging to events accepted from Axigen WebMail remain in the Calendar.app INBOX. 

  • At this point we have not found a way to tell Calendar.app to dismiss a notification that has already been processed outside the Calendar.app (in our case in WebMail).

• Calendar.app cannot create events with custom monthly rules (repeats monthly on the 12th, 14th, and 26th).

  • The Axigen Calendar API is unable to parse the RRULE created by Calendar.app.

• Calendar.app ↔︎ WebMail / Outlook connector interoperability issue 

  • Calendar.app has a different interpretation to RRULEs when interpreting yearly recurrent events.

  • It interprets the DTSTART as the first occurrence of the event, event if it does not match the date when the event repeats itself.

  • WebMail and Outlook however, display events only for those days that match the repeating rule.

• CalDAV ↔︎ WebMail interoperability issue 

  • When an Axigen user is organizer in an event and the event is created by a CalDAV client (e.g. Calendar.app) editing the event via WebMail causes the event to be canceled.

  • Calendar.app adds an ATTENDEE property for the organizer in the VCALENDAR.
    When WebMail edits the VCALENDAR it removes the ATTENDEE property above.

  • The calendar API detects a change in the calendar object (an attendee has been removed) and sends a cancellation message to that attendee (in our case the organizer).

• Axigen does not send attendee notifications for local folders that are not the default folder (Calendar)

  • Axigen current implementation - present in WebMail too.

• Only events from the Calendar folder are taken into account when computing FreeBusy.

  • In Axigen no other local calendar folders implement FreeBusy.

• Large calendar events (e.g. w/ attachments) can't be synchronized via CalDAV

  • Attempting to sync large events (e.g. uploading a calendar that's 12K or bigger → eM Client attachment → triggers error)