126.96.36.199 PidLidAppointmentSubType Property
The PidLidAppointmentSubType property ([MS-OXPROPS] section 2.31) specifies whether the event is an all-day event, as specified by the user. A value of TRUE indicates that the event is an all-day event, in which case the values of the PidLidAppointmentStartWhole property (section 188.8.131.52) and the PidLidAppointmentEndWhole property (section 184.108.40.206) MUST both be midnight so that the duration is a multiple of 24 hours and is at least 24 hours. A value of FALSE or the absence of this property indicates that the event is not an all-day event. Note that the client or server cannot infer the value as TRUE when a user happens to create an event that is 24 hours long, even if the event starts and ends at midnight.