The SynoExt add-on for Firefox is great for people who have a Synology DiskStation: downloading torrents on the NAS straight from the browser.
Too bad the extension isn’t being maintained, and is now incompatible with new Firefox versions (everything newer than 3.6 won’t work).
Turns out that there is a very easy fix, simply editing the ‘install.rdf’ and increasing a version number is enough to make it work in Firefox 4, 5 and 6.

Download SynoExt 0.7 for Firefox 4, 5 and 6.