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:
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
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.
an inline version, and
MediaObjectCO, a media object
For now, media objects and graphics exist together
in version 5.0.
be removed from DocBook.
A figure wrapper without a title. This element was added largely for symmetry.
Section is a recursive section. It exists
parallel to, and must be used as an alternative to,
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
VarName was added.
A tag for identifying variable values does not seem as necessary.
For immutable values, a specific tag other than
seems unnecessary, and
Replaceable exists for values that
are supposed to be filled in by the user.
DocBook V4.1 and DocBook XML V4.1.2 became an OASIS Standard in February 2001.
DocBook V4 introduced a number of backward-incompatible changes.
The policy of the DocBook TC is that backward-incompatible changes can only be introduced in a full version release. They must also be described in comments in the DTD at least one full version earlier. In other words, all the planned version 4.0 incompatibilities were announced with version 3.0.
Backward-incompatible changes to DocBook that are planned for version 4.0:
DocInfo element will be split out into
and so on.
ArtHeader will be renamed to
SeriesInfo may be
discarded because it has become a special case of
BookBiblio will be discarded in favor of a new, more inclusive,
BookInfo (and for
ArticleInfo, whose earlier
%article.class; entity may be removed from the
Book content model,
and made part of a new top-level document hierarchy.
%nav.class; entity, which appears in several divisions, will allow
ToCchap instead of
MsgText will be moved from
%tech.char.class; to a more appropriate
The following elements will have their content constrained to the
Affiliation will be removed from
and a new wrapper element will be created to allow association of those two
Author name information.
Epigraph will not be appearing in
Comment will be renamed to
Remark and will be excluded from itself.
GlossTerm will be excluded from itself, and may be split into an
element that appears in a
Glossary and an element that can appear in
the main text.
Subject attribute on
GlossDef will be renamed
SegTitle elements will be required in
InlineGraphic will be declared EMPTY. This change will
require that end tags be removed and that any embedded graphic content
be stored outside the SGML source and pointed to from an
ReqMult values for the
Choice attribute on
will be removed. Use the
Rep attribute instead to indicate that the
choice is repeatable.
The content model group inside
FuncSynopsis starting with
will not be available; you will have to use
FuncPrototype. Also, you
will be able to have a mixture of
(this is not backward-incompatible all by itself).
Prompt values for the
Class attribute on
will be eliminated; use the
Prompt elements instead.
DocBook V4.2 fixed a couple of small bugs and introduced a number of new features. Changes in DocBook V4.2 are explained in the DocBook Document Type Version 4.2.