vCard header: X-MS-ANNIVERSARY:, X-ANNIVERSARY:
vCard data format: X-MS-ANNIVERSARY:[date or date/time value]
Brief description: The wedding anniversary that is associated with the object that is represented by the vCard.
Importing to and Exporting from Contact Objects
The X-MS-ANNIVERSARY type is imported to and exported from the PidTagWeddingAnniversary property ([MS-OXOCNTC] section 188.8.131.52.4). The time that is associated with the anniversary event SHOULD<4> be 0:00 in the client's local time zone.