Right now I'm using the latest beta version of Firefox and found that I can't download a lot of plugins. Fortunately there is a way to make all the older plugins of Firefox work with any Firefox version. Here is how to do it. 1. Download Firefox Nightly Test Tools Firefox addon. Here is the link: https://addons.mozilla.org/en-US/firefox/addon/6543 2. Go to Tools -> Addons and click "Override all compatibility". 3. You'll see a list of all incompatible addons, just click "Force Install" This has worked for me for all the addons I've used so far.