As for the suggestion there: "Start out by reviewing a patch or responding to email on the lists. Even if it is unrelated to what you're doing", i'll look around other posts in this list.
For back versions, i think because this patch changes xpath() behavior, we will only apply this to future versions. The old behavior is wrong (according to XPath standard) for not including namespaces, but maybe there are some application that depends on the old behavior.