Appointment Type
There are five appointment types available.

Regular appointments (Type: 0)
Appointments that last for the specific period of time and never occur again.
Pattern (Type: 1)
Stores the rule according to which visible (to users) recurring appointments are generated.
Occurrences (Type: 2)
All appointments in a series, visible to users "clones" of a pattern appointment.
Changed Occurrence (Type: 3)
A former series member (occurrence) whose data has been modified. Changed occurrences are marked with a crossed-out occurrence icon.

Deleted Occurrence (Type: 4)
A regular or edited occurrence that has been removed while the rest of the series still exists.