DAV property names: urn:schemas:calendar:lastmodifiedtime, DAV:getlastmodified

Data type: PtypTime ([MS-OXCDATA] section

The PidTagLastModificationTime property ([MS-OXCMSG] section gets or sets the date and time when the appointment was last saved.

This property can have a different value in the appointment of the organizer and in the copy of each attendee. The server SHOULD update this value when any method saves an appointment.

For more details about the PidTagLastModificationTime property, see [MS-OXPROPS] section 2.764.