3023 RFC - A Mechanism for Creating More Specific Identifiers for XML Identified as, "text/xml"

http://www.ietf.org/rfc/rfc3023.txt

The value of the Content-Type header is constant within XML-RPC; it is the Internet media type for XML, "text/xml" XML-RPC appeared before RFC 3023, which specifies a mechanism for creating more specific identifiers for xml types. If one builds XML-RPC implementations that accept other flavors of XML identified as, "text/xml"( as well as XML-RPC over the same port), one will need to identify XML-RPC messages by the methodCall root element.