Non-normative information

In this section:

1. Changes from previous versions
   (Non-normative) The following topics outline the changes from earlier versions of DITA to the current version.
2. Migrating from DITA 1.1 to 1.2
   (Non-normative) DITA 1.2 is compatible with prior versions of the DITA specification in that all valid DITA 1.0 and 1.1 documents are valid DITA 1.2 documents. However, some changes to existing document type shells and specializations might be needed in order to maintain the same behavior under DITA 1.2 or to take full advantage of new DITA 1.2 features.
3. DITA MIME type
   (Non-normative) It is common for Web-based services to establish default actions for content based on the MIME type value sent in HTTP headers. For example, the "text/html" MIME type is what normally causes browsers to interpret the content of a web page as presentation-oriented markup, verus "text/plain" which would cause the markup to be displayed literally. A DITA MIME type enables applications to recognize content as DITA to enable special services such as semantically-informed search indexing or on-the-fly rendering in the browser.
4. Considerations for generalizing <foreign> elements
   (Non-normative) Generalization of a DITA element employs the value of its @class attribute. The content of a <foreign> element, or of a specialization of the <foreign> element, cannot be generalized because there are no DITA elements in it, and therefore no @class attributes. The non-DITA contents can only be processed by appropriate non-DITA means.
5. Element-by-element recommendations for translators
   (Non-normative) This topic contains a list of all OASIS DITA elements. It includes recommendations on how to present the element type to translators, whether the element contents are likely to be suitable for translation, and whether the element has attributes whose values are likely to be suitable for translation. Examples of content that is not suitable for translation include code fragments and mailing addresses.
6. DITA module and shell implementation reference
   (Non-normative) The DITA standard defines a set of base types and vocabulary modules and a set of specialized map types, topic types, and domains.
7. DTD organization
   (Non-normative) The OASIS DITA document types are implemented with a set of DTD modules. Some of these modules are used by every DITA document type, others are only used by topics or by maps, and some are only used in specific specializations.
8. XML schema organization
   (Non-normative) The OASIS DITA document types are implemented with a set of schema modules. Some of these modules are used by every DITA schema document, others are only used by topics or by maps, and some are only used in specific specializations.
9. Processing component modularization and naming conventions
10. Processing interoperability considerations
    (Non-normative) The DITA specification does not require processors to perform filtering, content reference resolution, key space construction, and other processing related to base DITA semantics in any particular order. This means that different conforming DITA processors may produce different results for the same initial data set and filtering conditions. DITA users and DITA implementers need to be aware of these potential differences in behavior when DITA content will be processed by different processors.
11. Specialization design, customization, and the limits of specialization
    (Non-normative) The DITA specialization facility necessarily imposes some constraints. An inherent challenge in designing DITA vocabulary modules and document types is understanding how best to satisfy markup requirements within those constraints and, when requirements cannot be met within the DITA-defined constraints, how to create "customized" document types that diverge from DITA requirements as little as possible.