The OASIS DocBook TC  members have recently approved a Committee Specification Draft (CSD) and submitted it for 30-day public review:
DocBook Version 5.1
Committee Specification Draft 01 / Public Review Draft 01
11 Feb 2015
DocBook is a general purpose [XML] schema particularly well suited to books and papers about computer hardware and software (though it is by no means limited to these applications).
The Version 5.1 release introduces assemblies for topic-oriented authoring. It also addresses a selection of bugs and feature requests.
The Technical Committee provides the DocBook 5.1 schema in other schema languages, including W3C XML Schema and an XML DTD, but the RELAX NG Schema is the normative schema.
The DocBook Technical Committee maintains the DocBook family of schemas.
Public Review Period:
The public review starts 23 March 2015 at 00:00 UTC and ends 21 April 2015 at 23:59 UTC.
This is an open invitation to comment. OASIS solicits feedback from potential users, developers and others, whether OASIS members or not, for the sake of improving the interoperability and quality of its technical work.
Reviewers may provide comments directly from the comment-tag version of document. The file
contains the HTML version of the draft with a “[comment?]” link next to each section heading. Clicking on this link will launch your email application and begin a message to email@example.com with the specific section number and title in the subject line. Simply enter your comment and click send.
Note that you must be subscribed to the comment mailing list before sending feedback. Instructions on how to subscribe can be found at https://www.oasis-open.org/committees/comments/index.php?wg_abbrev=docbook.
The prose specification document and related files are available here:
HTML with inline tags for direct commenting:
RELAX NG Schemas:
DocBook V4.x conversion tools:
ZIP distribution file (complete):
For your convenience, OASIS provides a complete package of the prose document and related files in a ZIP distribution file. You can download the ZIP file here:
Additional information about the specification and the OASIS DocBook TC can be found at the TC's public home page:
Comments may be submitted to the TC by any person through the use of the OASIS TC Comment Facility which can be used by following the instructions on the TC's "Send A Comment" page, or directly at:
Comments submitted by TC non-members for this work and for other work of this TC are publicly archived and can be viewed at:
All comments submitted to OASIS are subject to the OASIS Feedback License, which ensures that the feedback you provide carries the same obligations at least as the obligations of the TC members. In connection with this public review of "DocBook V5.1", we call your attention to the OASIS IPR Policy  applicable especially  to the work of this technical committee. All members of the TC should be familiar with this document, which may create obligations regarding the disclosure and availability of a member's patent, copyright, trademark and license rights that read on an approved OASIS specification.
OASIS invites any persons who know of any such claims to disclose these if they may be essential to the implementation of the above specification, so that notice of them may be posted to the notice page for this TC's work.
========== Additional references:
 OASIS DocBook TC
RF on Limited Terms