The Pale Moon team plans to remove support for Mozilla AMO (Add-ons Mozilla Org) from the web browser on May 8th, 2018.

Pale Moon is largely based on Firefox code, but compatibility took a hit recently when Mozilla switched the add-on system of Firefox to support WebExtensions exclusively while Pale Moon stayed with the what Mozilla calls legacy add-on system.

Only Firefox 52 ESR supports the legacy add-on system right now, and that support is removed with the release of Firefox 60 ESR. Starting with Firefox 60 ESR, no official version of the Firefox web browser will support legacy add-ons.

Mozilla announced plans to remove legacy add-ons from the official Firefox add-on repository after the launch of Firefox 60 ESR.

This decision impacts the Pale Moon browser in several ways as Mozilla AMO is integrated into current browser versions.

Pale Moon users can run searches on the browser’s about:addons website and install add-ons directly from the interface. Add-ons installed from Mozilla AMO use Mozilla’s automatic update service to check for add-on updates and install any that are found.

External add-on listings on the official Pale Moon add-ons repository, addons.palemoon.org, may point to Mozilla AMO as well.

The functionality breaks if Mozilla removes legacy add-ons from AMO. Pale Moon does not support the WebExtensions format. The development team of Pale Moon decided to remove support for Mozilla AMO from Pale Moon as a consequence.

What it means for Pale Moon users

First the good news. While Pale Moon won’t support searching about:addons for add-ons hosted on Mozilla AMO anymore, users of the browser may still install legacy add-ons from AMO directly.

Installing add-ons hosted on AMO works only for as long as classic add-ons remain hosted on Mozilla’s website. One downside is that add-ons won’t update automatically anymore because of the removal of the automatic update service that takes care of Mozilla hosted add-ons.

The removal means that Pale Moon users will have to visit the add-on pages manually to find out about updates and install them if that is the case.

Add-ons from AMO installed in Pale Moon already will be affected in the same way. They continue to function normally, but they won’t be updated automatically anymore.

Tip: Check whether the add-on is hosted at the Pale Moon add-on repository. If it is, install it from there instead. Add-ons installed from the official repository use Pale Moon’s automatic update service. You may also want to consider downloading any add-on from Mozilla AMO before Mozilla starts the removal of legacy add-ons.

Developers may upload their add-ons to Pale Moon’s add-on repository to keep it available online. There is also the possibility that add-ons may get forked before they are pulled from Mozilla AMO.

There is also an effort underway to archive all classic add-ons of the Firefox web browser.

Closing Words

Mozilla will pull classic add-ons from the Firefox add-ons site eventually at which point several built-in features of Pale Moon will stop functioning correctly that rely on it. The removal of these features is the only logical consequence. While users may not be thrilled about that, there is no doubt that this is the only option available.

Pale Moon users can install classic add-ons from AMO afterward until the add-ons get removed by Mozilla. It seems unlikely that many add-on developers will support legacy add-ons after the release of Firefox 60 ESR anyway.