The Exchange ActiveSync: Data Types describes the required format of each data type used by the ActiveSync XML schema definitions (XSDs).
This protocol sends and receives data in Wireless Application Protocol (WAP) Binary XML (WBXML) format. To ensure that both the client and the server have the same expectations about the format of the element data, the ActiveSync commands and classes use XSDs to define the data type of each element.
Sections 1.7 and 2 of this specification are normative and can contain the terms MAY, SHOULD, MUST, MUST NOT, and SHOULD NOT as defined in RFC 2119. All other sections and examples in this specification are informative.