2.2.4.2 PidLidAppointmentLastSequence Property
Type: PtypInteger32 ([MS-OXCDATA] section 2.11.1)
The value of the PidLidAppointmentLastSequence property ([MS-OXPROPS] section 2.15) indicates to the organizer the last sequence number that was sent to any attendee. For details about when and how a client increments the sequence number, see section 3.1.5.4. This property has no meaning for an attendee.