DocBook V5.x will be backwards incompatible

The DocBook Technical Committee has long operated under to the
following rule: backwards incompatible changes can only be introduced
at a major version change (e.g, V4.x to V5.0) and only if the changes
were announced in the previous major version (e.g., V4.0).

At the 17 Mar 2004 meeting[1], the TC voted to grant itself a one-time
exception to this rule. It has been a long time since V4.0 and quite a
few backwards incompatible changes have collected in the intervening
years. In addition, according to our current plans, the DocBook V5.0
release will be based on a RELAX NG schema. Changing validation
technologies is an opportunity to clean up a number of long-standing
issues and the TC intends to do just that.

As a result, the DocBook V5.0 schema is expected to contain backwards
incompatible changes that were not announced in V4.0.

A complete list of these planned changes will be published as soon as
it is available.

                                        Be seeing you,
                                          norm

[1] http://lists.oasis-open.org/archives/docbook/200403/msg00032.html

-- 
Norman Walsh <>      | A philosophical contempt of life
http://www.oasis-open.org/docbook/ | is no guarantee of courage in the
Chair, DocBook Technical Committee | face of death.--Gustave Vapereau