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.