Installing and Updating
You can install the released version from the Mozilla Add-ons page or Firefox’s “Tools > Add-ons” window.
Try The Beta Version
You can install the beta version to get the latest more features (but maybe a bug or two).
Normally Firefox will automatically check for updates when you start Firefox, or you can check for yourself on the Mozilla Add-ons page.
Questions / Feedback
Please review the add-on on the Mozilla Add-ons page but to report a bug it’s more effective to use email, Facebook, or WordPress, since I can follow-up for more info.