Last year, Mozilla gave Firefox the upgrade it deserved. Firefox Quantum offered a new and improved interface, faster page loading, better use of memory, integrated screen shots, and story saves via Pocket, which Mozilla acquired in 2017.
Quantum also pretty much killed off Firefox extensions as we know them. That’s because the old extensions had too much power. A bad extension could bring the whole browser to its digital knees—a bad look, security-wise. Several years ago, Mozilla introduced WebExtensions, a programming interface for developers that limited extensions, but still gave them some juice. As of Quantum, the only extensions supported are those created with WebExtensions—the older ones don’t work.
So if you upgrade to the latest Firefox (version 58 as of this writing), you need to get all new versions of your favorite extensions. Many just won’t get an upgrade, and you’ll have to find something new.
If you’re new to Firefox, or perhaps returning after an extended hiatus, now’s the time to start clean with Quantum and grab the newest add-ons. That term encompasses the productivity extensions and the interface-enhancing themes you can grab for free to personalize the look of the Firefox menu bar. If you ever want to disable, uninstall, or change options on one, type about:addons in the Firefox address bar and click Extensions.