188.8.131.52 XML Streams
The message MUST have the PidTagRoamingDatatypes property (section 184.108.40.206) set. The value of the property MUST be a bitmask that includes 0x00000002.
The message MUST have the PidTagRoamingXmlStream property (section 220.127.116.11) set. The value of the property MUST be a PtypBinarystream (2) that contains a UnicodeXML document that is using the UTF8 encoding.
If the application encounters unknown XML elements while parsing the document, it SHOULD preserve those elements without modification and include them whenever it makes modifications to the parts of the document that it understands.