For the form template, I'd just open it in design mode, save as InfoPath 2013, and publish to the new server however you usually publish it (i.e. admin approve, directly to the library, as a content type). Update any data connections that IP doesn't offer to update automatically for you (I'm working on the assumption the URL will be changing). For the XML - I'd just copy those into the new form library, change to the relink view (may have to view the library in "Classic mode" to find that) and relink all the XML to the currently published template.
Hilary Stoupa
