On Thu, Oct 6, 2011 at 3:57 PM, Roan Kattouw <roan.kattouw@gmail.com> wrote:
On Thu, Oct 6, 2011 at 3:52 PM, Nicolas Vervelle <nvervelle@gmail.com> wrote:
> Hi, thanks for answers.
>  Well, I'm using XPath in Java to find informations in the XML answer.
> Unless I missed something, I think I have to change a lot of things, and
> can't have my tool compatible with both 1.17 and 1.18.
I was told by the people on Bugzilla (see
https://bugzilla.wikimedia.org/show_bug.cgi?id=24781 ) that there
wouldn't be any problems unless people were doing ugly things like
regexing or something. Perhaps you should ask for help there. I know
nothing about XML namespaces, I just did what my fellow MW devs asked
me and had their assurance it wouldn't break things.

I'm not doing any strange regexping, and everything I read on XPath and default namespace seems to point that XPath expressions are not compatible between a document without a default namespace (API 1.17) and a document with a default namespace (API 1.18).
Comment #12 on bug 24781 is about the same problem : the change breaking code using XPath expressions.