It's happening! HOORAY! I've been using 32-bit Firefox for way too long. This addon is important to me. I've been waiting and waiting for this to be 64-bit compatible through an update to finally jump the ship to 64-bit Firefox, it's gotten depressing... until today! Windows 10 here running 64-bit Firefox. This addon works. Apparently just updating this addon doesn't seem to work, then I've uninstall this addon and the actual iCloud software off from my PC then reinstall both and they work.