(published in RFC 3023 in January 2001, last updated 2014-04-17 via RFC7303) Type name: text Subtype name: xml Required parameters: none Optional parameters: charset See Section 3 of RFC7303. Encoding considerations: Depending on the character encoding used, XML MIME entities can consist of 7bit, 8bit or binary data [RFC6838]. For 7-bit transports, 7bit data, for example US-ASCII- encoded data, does not require content-transfer-encoding, but 8bit or binary data, for example UTF-8 or UTF-16 data, MUST be content- transfer-encoded in quoted-printable or base64. For 8-bit clean transport (e.g. 8BITMIME ESMTP [RFC6152] or NNTP [RFC3977]), 7bit or 8bit data, for example US-ASCII or UTF-8 data, does not require content-transfer-encoding, but binary data, for example data with a UTF-16 encoding, MUST be content-transfer-encoded in base64. For binary clean transports (e.g. BINARY ESMTP [RFC3030] or HTTP [HTTPbis]), no content-transfer-encoding is necessary (or even possible, in the case of HTTP) for 7bit, 8bit or binary data. Security considerations: See Section 10 of RFC7303. Interoperability considerations: XML has proven to be interoperable across both generic and task-specific applications and for import and export from multiple XML authoring and editing tools. Validating processors provide maximum interoperability, because they have to handle all aspects of XML. Although a non-validating processor may be more efficient, it might not handle all aspects. For further information, see sub-section 2.9 "Standalone Document Declaration" and section 5 "Conformance" of [XML] . In practice, character set issues have proved to be the biggest source of interoperability problems. The use of UTF-8, and careful attention to the guidelines set out in Section 3, are the best ways to avoid such problems. Published specification: Extensible Markup Language (XML) 1.0 (Fifth Edition) [XML] or subsequent editions or versions thereof. Applications that use this media type: XML is device-, platform-, and vendor-neutral and is supported by generic and task-specific applications and a wide range of generic XML tools (editors, parsers, Web agents, ...). Additional information: Magic number(s): None. Although no byte sequences can be counted on to always be present, XML MIME entities in ASCII-compatible character sets (including UTF-8) often begin with hexadecimal 3C 3F 78 6D 6C ("