The Content-Type header indicates the format of the data sent in the request body. When the request body for a command is in WBXML format, the Content-Type header value MUST be set to either "application/vnd.ms-sync.wbxml", or the shortened string "application/vnd.ms-sync". The shortened string is not allowed by protocol versions 2.5 and 12.0.

For the Autodiscover command ([MS-ASCMD] section, which specifies an XML request body format, the Content-Type header SHOULD be set to "text/xml" or MAY<3> be set to "text/html". If the request has no body, the Content-Type header SHOULD NOT be present.