3.2.1.1.3 Exceptions to a Recurrence

Exceptions are a single appointment that overrides one instance of a recurring appointment. The starting date and time of the overridden instance is the replacement date-time of the exception. Exceptions are in the time zone of the recurrence they belong to.

Any property of a recurrence that is missing from an exception is assumed to have the same value as other instances of the recurrence. This means an exception with no location to a recurrence with location="xyz" has a location "xyz". All properties of an exception override properties of a recurrence. This means if an exception has a different starting date and time than the instance it replaces, the protocol client MUST use the exception’s starting date and time for that instance.

When a recurrence is deleted, all exceptions to that recurrence SHOULD also be deleted. Protocol clients MAY instead choose to convert or display them as other appointment types.<13>

Exception items SHOULD only be converted to deleted instance items. Exception items MAY be deleted to restore the original recurring instance.<14> Exception items can also be converted to single appointment items, in which case the protocol client decides whether the replaced instance can be restored, an exception, or deleted by uploading a replacement exception item.