Seems a very wise feature add to pndmanager, or as a separate pnd program.
Something that can backup the appdata folders if removing a pnd, or upgrading, as many updates suggest a new folder is wise (requiring exit of pndmanager & manual backup of the old folder for save states and such), prior to being able to just use pndmanager to relaunch the new version.
Plus not all pnd have obviously named appdata folders, making tracking them down more of a less user friendly experience and potential sd card bloat in obsolete appdata folders.
Ideally it should offer to backup the old version of a pnd and it's appdata folder as well, to separate locations and be able to restore them if wanted, after testing the updated version.
It should also offer light refreshments cooked by dragon fire