From a UX POV, when I'm searching docs I'm likely to be working on a site of a specific version - results of docs from older or newer versions are likely to be less relevant to me. If I want to search wider after my initial search I can use the check boxes on the advanced search.
This major update changes the behaviour of the docviewer module to use a cached manifest rather than on demand. This allows us to simplify the URL matching and store 'nice' URL configuration rather than altering handleAction().