The World Wide Web Consortium has now issued XHTML 1.1 - Module-based XHTML as a W3C Recommendation, indicating that the XHTML 1.1 specification "is stable, contributes to Web interoperability, and has been reviewed by the W3C Membership, who are in favor of supporting its adoption by academic, industry, and research communities. The specification defines a new XHTML document type that is based upon the module framework and modules defined in Modularization of XHTML. The purpose of this document type is to serve as the basis for future extended XHTML 'family' document types, and to provide a consistent, forward-looking document type cleanly separated from the deprecated, legacy functionality of HTML 4 that was brought forward into the XHTML 1.0 document types. The XHTML 1.1 document type is essentially a reformulation of XHTML 1.0 Strict using XHTML Modules. This means that many facilities available in other XHTML Family document types (e.g., XHTML Frames) are not available in this document type. These other facilities are available through modules defined in Modularization of XHTML, and document authors are free to define document types based upon XHTML 1.1 that use these facilities. The document type is designed to be portable to a broad collection of client devices, and applicable to the majority of Internet content. Content developers who base their content upon XHTML 1.1 can trust that it will be consistently portable across user agents which support XHTML."

From the announcement and Introduction: "XHTML 1.1 Provides Clean Web Foundation through Modularity. XHTML 1.1 is the latest development in a series of W3C work to ensure the universality of content formats for the Web. The first step was to reformulate HTML 4 in Extensible Markup Language (XML), resulting in XHTML 1.0. Like HTML 4, the reformulation carried three variants: Strict; Frameset; and Transitional. These gave content developers, often not accustomed to producing valid markup, choices in markup, though not choices that could be supported by all devices. The next step was to modularize the elements and attributes into convenient collections for use in documents that combine XHTML with other tagsets. The modules are defined in Modularization of XHTML. XHTML Basic is an example of fairly minimal build of these modules and is targeted at mobile applications. XHTML 1.1 is an example of a larger build of the modules, avoiding many of the presentation features... With the advent of the XHTML modules defined in Modularization of XHTML, the W3C has removed support for deprecated elements and attributes from the XHTML family. These elements and attributes were largely presentation oriented functionality that is better handled via style sheets or client-specific default behavior. Going forward, XHTML family document types will be based upon this new, more structural functional collection..."

Bibliographic information: XHTML 1.1 - Module-based XHTML. Reference: W3C Recommendation 31-May-2001. Edited by Murray Altheim (Sun Microsystems) and Shane McCarron (Applied Testing and Technology). Latest version URL: http://www.w3.org/TR/xhtml11. Previous version URL: http://www.w3.org/TR/2001/PR-xhtml11-20010406. Available as a single file HTML version, PostScript version, PDF version, and ZIP archive.