# I. Changes from XHTML Modularization 1.0

This appendix is informative.

This specification supercedes XHTML Modularization 1.0. This section describes at a high level the changes from that version. This section does not attempt to address the various editorial corrections that were made. For a detailed comparison, see the "diff marked" version from that recommendation.

- Global Changes
  - Introduction of an XML Schema implementation. This includes the development of a Modularization technique to be used with XML Schema, and the actual implementation of the abstract modules using that technique.
  - Clarified that in XHTML Family Languages the "default" behavior of XML whitespace processing is "preserve" as defined in [XML].
- Section 2 - Terms and Definitions
  - Added a definition of the term "facilities".
- Section 3 - Conformance Definition
  - Clarified that attributes from the XHTML namespace can be used on elements NOT in the XHTML namespace, but they should be namespace-qualified.
  - Clarified the rules for processing of unrecognized elements in conforming user agents.
  - Removed the whitespace handling rules, deferring instead to the rules in [CSS2].
- Section 4 - Defining Abstract Modules
  - Removed `PCDATA` from the table of attribute types, since it is not an attribute type.
  - Clarified that Language Codes are defined by [BCP47].
  - Added a note that additional LinkTypes can be defined, but should be described in a profile.
  - Added a definition for the datatypes QName and QNames
  - Clarified that the datatype URI is the same as that of anyURI in [XMLSCHEMA].
- Section 5 - Attribute Collections
  - Clarified that attributes defined in XHTML attribute collections are available for use on elements in other namespaces if they are referenced using their namespace qualified form.
  - Added `xml:space` to the Core attribute collection, so that it is available on all elements. Also removed any explicit references to `xml:space` from other elements.
  - Corrected the definition of `xml:lang` to take `CDATA`, not `NMTOKEN`.
  - Added the `id` attribute to every element.
  - Corrected the minimal content model for `blockquote`.
  - Clarified that the Basic Forms Module cannot be used in conjunction with the Forms Module.
  - Clarified that the Basic Tables Module cannot be used in conjunction with the Tables Module.
  - Corrected the minimal content model for `legend` so that it can be empty.
  - Corrected the types of attributes on the `table` element in the Basic Tables Module.
  - Formally deprecated the Legacy Module.
  - Corrected the `align` attribute values on the `img` element in the Legacy Module.
  - Corrected the `height` attribute type on the `th` element in the Legacy Module.
  - Corrected the `width` attribute type on the `td` element in the Legacy Module.
- Appendices A, B, C - XML Schema Implementation

  This is new content in this specification. It was developed independently and has already gone through the W3C processes including Last Call.

- Appendix D - Building DTD Modules
  - Corrected an XMLNS reference in the Inventory module example.
  - Migrated references to XHTML Modules to "w3.org/MarkUp/" space instead of "TR" space.
- Appendix E - Developing DTDs with defined and extended modules
  - Migrated references to XHTML Modules to "w3.org/MarkUp/" space instead of "TR" space.
  - Corrected the handling of prefixed elements in the MyML example.
- Appendix F - XHTML DTD Module Implementations
  - Migrated references to XHTML Modules to "w3.org/MarkUp/" space instead of "TR" space.
  - Added "prefixed" declarations of global attributes for use in other, non-XHTML namespace markup languages.
  - Corrected the content model of body so that the body is permitted to be empty.
- Appendix G - References

  Updated references to make them current.

  - Added reference to [RFC3987].