All, The media type is defined in the W3C Candidate Recommandation of "XML-binary Optimized Packaging" [1] Below is a full test version for convenience [2] Please direct comments to xmlp-comments@w3.org. Best regards, [1] http://www.w3.org/TR/2004/CR-xop10-20040826/#N103C0 [2] MIME media type name: application MIME subtype name: xop+xml Required parameters: type This parameter conveys the content type associated with the XML serialization of the XOP infoset, including parameters as appropriate. Optional parameters: charset This parameter has identical semantics to the charset parameter of the "application/xml" media type as specified in RFC 3023 [RFC3023]. Encoding considerations: Identical to those of "application/xml" as described in RFC 3023 [RFC3023], section 3.2. Security considerations: In addition to application-specific considerations, XOP has the same security considerations described in RFC3023 [RFC3023], section 10. Interoperability considerations: There are no known interoperability issues. Published specification: This document Applications which use this media type: No known applications currently use this media type. Additional information: File extension: XOP Fragment identifiers: Identical to that of "application/xml" as described in RFC 3023 [RFC3023], section 5. Base URI: As specified in RFC 3023 [RFC3023], section 6. Macintosh File Type code: TEXT Person and email address to contact for further information: Mark Nottingham <mnot@pobox.com> Intended usage: COMMON Author/Change controller: The XOP specification is a work product of the World Wide Web Consortium's XML Protocol Working Group. The W3C has change control over this specification. -- Yves Lafon - W3C "Baroula que barouleras, au tiéu toujou t'entourneras."