As a top-level element of the Calendar class, the DtStamp element is an optional element that specifies the date and time that the calendar item was created or modified. It is used in ActiveSync command requests and responses as specified in section 2.2.2.
As an optional child element of the Exception element (section 126.96.36.199), the DtStamp element specifies the date and time that this exception was created. A command request or response has a maximum of one DtStamp child element per Exception element. If the DtStamp element is not specified as a child element of an Exception element, the value of the DtStamp element is assumed to be the same as the value of the top-level DtStamp element (section 188.8.131.52).
The DtStamp element is defined as an element in the Calendar namespace. The value of this element is a dateTime data type, as specified in [MS-ASDTYPE] section 2.3.