2.2.7 AsyncUI XML Notification and Response Formats
This section specifies the data formats for notifications and responses associated with the notification type identifier value AsyncPrintNotificationType_AsyncUI (section 2.2.1). The data formats are specified by using a combination of prose and XML schema syntax [W3C-XSD].
The XML schema fragments contained in this section are drawn from two separate XML schema documents, one for AsyncUI notifications and one for AsyncUI responses. Both schema documents specify a value of "qualified" for the elementFormDefault attribute of the root "schema" element.
The XML schema document for AsyncUI notifications MUST specify a targetNamespace attribute value of "http://schemas.microsoft.com/2003/print/asyncui/v1/request" and also MUST use that URI as the schema document's default namespace ([XMLNS] sections 2.1 and 3.0).
The XML schema document for AsyncUI responses MUST specify a targetNamespace attribute value of "http://schemas.microsoft.com/2003/print/asyncui/v1/response", and also MUST use that URI as the schema document's default namespace.
The XML data contained within AsyncUI notifications and responses MUST obey the syntax of well-formed XML 1.0 documents ([XML1.0] section 2.1). Furthermore, those documents MUST be encoded in UTF-16LE (Unicode Transformation Format, 16-bits, little-endian) ([RFC2781] section 4.2).
Note that XML 1.0 [XML1.0], restricts the set of legal characters that can be used. Values that cannot be expressed in XML MUST NOT be represented in an XML document contained within an AsyncUI notification or response. Furthermore, some legal characters, such as "<" and "&", require some form of escaping when encoded in XML. Implementations MUST use an XML-defined mechanism, such as CDATA ([XML1.0] sections 2.4 and 2.7) or numeric character references ([XML1.0] section 4.1), to encode such characters within XML documents.