How in the Tech

Allowing Firefox to install “incompatible” add-ons

By Adam Myers ⋅ July 8, 2010 ⋅ Tags: Firefox

Adventurous users are probably already aware that the latest incarnation of the Firefox browser was released as a public beta earlier this week – Firefox 4.0b1. In addition to numerous under the hood feature expansion, the most immediate change to users will be the new user interface which features a rather drastic departure from the traditional Firefox interface. If you’ve used Google Chrome or Opera, you’ve already seem some the influence they’ve had on Firefox 4. Quite simply, the interface is stunning – leverage Aero Glass in Windows and moving the tabs to the top of the browser Window (like Opera and Chrome ..).

I’ve been using the browser off and on since it’s release and the experience has been more or less positive. One niggling problem centers around Firefox’s greatest asset, it’s vast array of add-ons. Long-time Firefox users know that every major release of the browser brings about “incompatibilities” with add-ons developed for older versions of Firefox. The word incompatibility is put into quotes because for many add-ons, they work just fine and the whole process is just a safe guard to potential problems. The simplest approach to enabling these extensions is downloading and installing the Nightly Tester Tools extension. The extension effectively removes the browser version check on add-ons, thus keeping them enabled on the latest Firefox beta. This is often enough to allow for a return to full functionality – but it’s not always the case.

One of the catch-22′s in this process is quickly apparent if you’ve followed the link above and attempt to install the Nightly Tester Tools in the 4.0 beta. Firefox blocks the install because the add-on is not compatible!

It’s possible to disable this check thankfully, user beware, by venturing into Firefox’s about:config through the address bar.

Inside about:config, right-click anywhere and select New->Boolean.

In the resulting pop-up dialog, we want to create a Preference named extensions.checkCompatibility.4.0b

Finally, set the preference value to False.

The change is applied immediately; you should be able to return to the previously blocked extension install page, Nightly Tester Tools in our case, and continue with the installation.

You will be quite surprised to see many, if not all, your extensions work just fine in the latest beta. Nevertheless, there is always a possibility they won’t – where you are then in a waiting game for the developer to publish an updated extension.