http://www.docbook.org/tdg5/en/html/ch01.html#introduction-whats-new lists some of the new features of Docbook 5. The current style sheets will work with Docbook 5, but the process for rendering will have to be tweaked to account for the new name spaces. For example, a topic will not have the namespace definitions, as these will be supplied in the <book> or <article> root XML element. But without the namespaces define, some Docbook 5 elements will not render correctly e.g.: <section> <title>LS command</title> <para> <application xl:href="http://www.gnu.org/software/emacs/">Emacs</application> </para> </section> won't render as is. We need to add the name spaces so what is transformed is actually something like: <section xmlns="http://docbook.org/ns/docbook" xmlns:xl="http://www.w3.org/1999/xlink" version="5.0"> <title>LS command</title> <para> <application xl:href="http://www.gnu.org/software/emacs/">Emacs</application> </para> </section>
It looks like the standard GWT XML parser doesn't handle namespaces, so all processing done prior to rendering will have to be done with regexes and not through XML DOM manipulation.
Verified that basic examples work, however defining other namespaces seems to cause errors for the validation and rendering. See https://bugzilla.redhat.com/show_bug.cgi?id=1051921#c2 for more info.
Adding that I've tested the additional topic types to make sure they render: Revision History Author Group Legal Notice
Injections don't render or validate when the Topic Format is DocBook 5.0 due to the injection resolver using <ulink>s. It should now be something like: <link xlink:href="...">Topic 10</link>
I've fixed up the Injection linking issue in 1.4-SNAPSHOT build 201402101456
Automatic namespace addition has been removed, so all namespaces are now manually defined in the topic.
Verified that rendering works as expected taking into account the issue with having to use a DTD for validation (ie no custom namespaces)
Moving this back to assigned as something has broken this in additional updates. Legal Notice and Author Group no longer renders.
Fixed in 1.4-SNAPSHOT build 201402141412 The namespaces were being applied before the <authorgroup> or <legalnotice> elements were wrapped. There was also an issue with the getRootElementName where it was returning more than it should have been.