The OASIS DocBook Technical Committee (TC) is committed to the continued evolution of DocBook. As new needs are expressed by the DocBook-user community, the committee will adapt DocBook so it continues to meet the needs of its users.
The TC observes a very cautious policy regarding changes to the DTD. Backward-incompatible changes can only be introduced:
Changes made at point-releases are always backward-compatible to the previous major release. This policy assures that DocBook users always have time to prepare for any coming changes.This appendix describes the changes planned for DocBook.
DocBook V3.1, released in February 1999, introduced a number of new elements:
MediaObject is a wrapper around VideoObject, AudioObject, ImageObject, and TextObject. The purpose of MediaObject is twofold: first, it introduces new element types to include video and audio content; second, it provides the option of alternative representations, including text, for objects in a document. MediaObjects also allow Captions that may be longer than a simple title.
Parallel to MediaObject are InlineMediaObject, an inline version, and MediaObjectCO, a media object with Callouts.
For now, media objects and graphics exist together in version 5.0. Graphic and InlineGraphic will be removed from DocBook.
A figure wrapper without a title. This element was added largely for symmetry.
An end-of-the-book Colophon.
Section is a recursive section. It exists parallel to, and must be used as an alternative to, Sect1.
The Constant inline is for identifying constants. It has a Class attribute for identifying “limits” as a specific kind of constant.
Many authors have requested a tag for identifying variable names. Most often Literal (with or without a role) has been chosen as a compromise, but you can't question the utility of identifying variable names, so VarName was added.
A tag for identifying variable values does not seem as necessary. For immutable values, a specific tag other than Literal seems unnecessary, and Replaceable exists for values that are supposed to be filled in by the user.