|User since||Nov. 13, 2008|
|Number of add-ons developed||0 add-ons|
|Average rating of developer's add-ons||Not yet rated|
Make usable for later versions Rated 5 out of 5 stars
Save the .xpi (right-click Add to Firefox -> Save as -> open using winrar, or the like -> extract install.rdf -> edit using notepad or equivalent for your OS -> find <em:maxVersion> -> change to *.* -> add back to .xpi using winrar -> install
It works for me.