Mozilla starts to disable legacy Firefox add-ons downloads next month


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Mozilla will stop offering legacy Firefox extensions as they are soon also no longer supported by the browser. At the end of 2017, Mozilla launched a new Firefox architecture called Quantum that only supports extensions based on the WebExtensions model.


Waiting since long time for updates of old addons, but still many addons are still old type


If the developers really want user to show interest it is in their best interest to update them.


Great. I guess users of browsers like SeaMonkey and Pale Moon are left high and dry. Once again, Mozilla’s screwing users over.

Look, I (kind of) get that mozilla wants a more modern add-on API, but couldn’t they keep their older add-ons up for archival purposes or something? Perhaps they could move them somewhere else, e.g. or

I guess users like me will have to start using the Internet Archive’s WayBack Machine from now on.


Well it’s not FF fault if addons don’t want to update or are abandonware. That’s not FF fault and they have to protect their Browser.


The WebExtensions API simply doesn’t allow for various features that the previous architecture allowed (which was virtually anything, leading to many of users’ favorite addons to begin with), and given Mozilla haven’t implemented some of the requested features to into the new API at dev’s requests the ball kind of is in Firefox’s court in some cases.

So I’d say for those it’s unfair to criticize devs for the lack of WE ports. I also have addons with versions dating back to 2013 that still work on the very last FF version prior to Quantum so additionally it was that some just retained their compatibility for a longer period than they were necessarily abandoned which is another thing to keep in mind.

I agree with the poster earlier that it’s a shame it had to be up to third-party volunteers to archive Firefox’s rich addon history—with no direct support from Mozilla—than keeping a read-only addon archive.


If I do recall some time back FF/Mozilla announced what they were going to do and it was up to the addon/extension makers to update to work with the latest FF coming out with their new security changes. So if they didn’t read or disregarded this notice then it’s in their court to fix as well.


I haven’t tried this in SeaMonkey or Pale Moon as I don’t have those browsers .
I did use it to install ublock in CyberFox.
It might even work if FF stops having ublock as an add on .

Just select Tools/Add Ons/Extensions in FF.
The the settings icon & “Install Add o from file”.
This may work the same in SeaMonkey or Pale Moon.


Have to remember FF hosts the addons if they past security and proper vetting some bad apples do make it through but the most part if the creators don’t support their own Addon making FF do so is asking for a whole load of rotten apples coming out. Just the sheer volume of Addons would cause FF development to stop.


You can actually install uBlock from github. If you use Pale Moon, you’ll have to select one of the “Firefox legacy” versions, since Pale Moon doesn’t support WebExtensions. Just use CTRL+f to search for “firefox-legacy.xpi”, and install the latest version.

There are also other addons available on Pale Moon’s webpage, including a few ad blockers, although I can’t say whether they’re any good.


Same github link as in my post.
Good hint of the CTRL+f for searching for the “firefox-legacy.xpi”.
That may work best in Pale Moon.
I don’t have Pale Moon so I don’t know.
For CyberFox the newest “uBlock0.firefox.signed.xpi” worked fine.


I can say from experience that the legacy builds are the ONLY builds that work in Pale Moon, as PM doesn’t support WebExtensions.

I can’t say for CyberFox, as I (ironically) don’t have it.


I was able to get a portable Pale Moon.
You are spot on about the legacy builds of ublock.
The newest one didn’t work as you said.
It gave the message " Pale Moon doesn’t support WebExtensions." .
The legacy one worked & did what I wanted.

Do you know of a browser cleaner like eCleaner for FireFox that works for Pale Moon ?

I also got DownloadHelper which is a legacy version of it added to Pale Moon portable.
I haven’t tested it yet.


I tend to like Click&Clean. There’s a WebExtensions version somewhere for modern Firefox, but the one linked here works fine on Pale Moon.

On a semi-related note, You can still find a good number of addons for Pale Moon on (at least as of this writing), but you might have to install old versions. Just go to the addon page, and click “See all versions” on the left.

Of course, as I mentioned a few posts ago, there are also addons made specifically for Pale Moon on the website.


I only use 4 addons that work and that is all I need.


In my Mozilla based browsers 4 is the number of extensions I use.
Then two plugins.