This is a quick announcement to let you know an “Edge” ISO image is now available for Linux Mint 20.3.

This image is made for people whose hardware is too new to boot the 5.4 LTS kernel included in Linux Mint 20.3. It ships with kernel 5.13.0-25 instead.

For information on Edge ISO images visit

Yesterday we announced a new partnership with Mozilla and a transition to Mozilla default settings in Firefox 96. If you didn’t read this announcement yet, please visit

Today, in preparation for Firefox 96 I want to make one more blog post, this time to talk specifically about technical details and to help people before, through and after the transition.

Firefox 96 is out today but we’ll publish the update on Friday January 14th. This will give everyone a few days to read this post, prepare for the update and get an opportunity to ask questions and seek help before the transition.


Impacted releases

This post is relevant for users of Linux Mint 19x, 20, 20.1, 20.2 and LMDE 4.

In Linux Mint 20.3 the transition already took place with Firefox 95 during the BETA (

Impacted browsers

Only the repository version of Firefox is impacted.

The flatpak version of Firefox already uses the Mozilla default settings. The Mozilla version (downloaded from their site) obviously also already uses it as well, and so do versions from PPA (ESR or not).

Other browsers are not impacted.

Nature of the changes

If you used Firefox in Windows or other Linux distributions you’re already familiar with Mozilla’s default settings.

We’re transitioning towards the same configuration as the one which is used everywhere else. The most noticeable changes are the search engines, the start page, and the preferences settings.

Impact on configuration (technical explanation)

The main impact is on the configuration. Because of the way settings work in Firefox, only settings which value is different from the default value are actually stored in your profile. As the default value changes, you can lose some configuration.

Say a particular setting defaults to A in Linux Mint but B in Mozilla. If you set it to C, then your profile contains a custom value. As we transition the default from A to B, you keep your C custom value.

Now, say you have it set to A. Since it’s identical to the default value, it is not custom, and so it’s not stored in your profile. To you it may look like something you set, but really you’re just using the default value, so this is actually not “set”. As we transition the default value from A to B, you simply transition from no custom value to no custom value, and thus also transition from A to B. From your own point of view this can create a gap between your expectation and the resulting configuration.

Before the update

Before the transition, make a backup copy of your profile and perform a system snapshot. This guarantees you’ll be able to go back and essentially removes any risk of losing anything.

System snapshot

To create a snapshot, open Timeshift and hit the Create button.

Profile backup

To make a backup copy of your profile, open a terminal and type:

cp -R .mozilla .mozilla-backup

Custom Policy file

Our packages will provide a policy file in /usr/lib/firefox/distribution/policies.json.

If you created a file under that path, it will be overwritten. Make a copy of it.

After the transition you can place your policy in /etc/firefox/policies instead.

After the update

Review your settings

In Firefox click on Settings and go through the tabs on the left to review your settings.

Set things to your liking and select your favorite search engine.

Spell check and dictionaries

On any website, right-click in a text area (i.e. a zone where you can enter text) and select “Languages”.

If you don’t see your language, select “Add Dictionaries…”.

Alternative solution

Alternatively, reinstall the package for your Firefox language pack. Type this command in a terminal to list your language packs:

dpkg -l firefox-l*

And then for each pack:

apt reinstall pack-name

Replace pack-name with the appropriate pack name. For instance, to reinstall the French language pack in Linux Mint, the command would be:

apt reinstall firefox-locale-fr

If you had added words to your dictionary and they are missing, look for a file called persdict.dat in your profile backup and copy it to your profile.

Custom Chrome CSS

If you had a custom chrome/userContent.css file and it goes missing, copy it over from your backup profile and enable the following setting in about:config:


Warning messages

Firefox cannot handle its own updates. It doesn’t know how to check the repositories and doesn’t have admin privileges anyway. In Linux Mint this is the job of the Update Manager so Firefox is told not to handle updates.

In the past, this was done via code changes. We patched Firefox not to do it and not to show any warning about it. This is how it is in Debian and Ubuntu as well.

With this transition this is done via a policy file, i.e. via system-wide configuration. Firefox shows the following messages in the preferences and in the about dialog as a result:

These messages can be quite confusing, especially the first one. Please ignore them for now. We’ll be reporting the issue to get it fixed upstream.

Comments section

The comments section on this post is exclusively dedicated to support. If you have questions, or you need help about the technical aspects of this transition then this is the right place.

We can’t “move” off-topic comments to the appropriate post here with WordPress. If something is off-topic we can either let it harm the topic or moderate it. Please respect this so we have this space to interact on support and technical questions don’t get lost.

To talk about Firefox in general or the partnership with Mozilla comment at instead.

For any other topics use the forums or the other posts on this blog.

Thank you for your understanding and if you’re waiting on this update for your patience. I wish you all a smooth update and I hope you’ll enjoy your experience with Mint and Firefox after this transition as much or even more than before.

Linux Mint signed a new partnership with Mozilla.

Mozilla develops two of the most important software applications in our distribution:

  • The Firefox Web Browser
  • The Thunderbird Email and Calendar application

Mozilla is one of the Open Source greatest champions of all time. It played a unique role throughout history in the promotion of Free Software and greatly contributed to the success of Linux.

In the 90’s Netscape Navigator was the most popular Web browser but it quickly lost its lead to Internet Explorer which came bundled with Microsoft Windows. The Web was changing rapidly, Explorer was dominant (it reached 95% user share in 2003) to the point where most websites no longer cared about compatibility with other browsers or operating systems and we got in a situation where Microsoft de-facto dictated Web standards.

Netscape did something formidable at the time. It released its source code to the World. Mozilla was formed to use that code and coordinate the development of a new Open Source browser, which eventually became Firefox. A few years later the Web was no longer dominated by a single browser. In 2010 Firefox represented 30% of the user share and Internet Explorer had gone down to 50%.

Firefox didn’t just save the Web, it promoted the idea of Free Software to millions of people who were using Windows, Mac or other proprietary operating systems. In the 2000’s, distribution shipped with Firefox, which many Windows users already knew and loved. This made it easier for people to migrate to Linux and distributions became more mainstream.

We have our champions. Pioneers and early adopters remember the importance of key projects and key personalities in the history of Linux and of Free Software. I remember using Netscape on Unix terminals at the university, even before we had Linux at home. I remember having the best browser available at a time when even getting a sound card to work in our favorite operating system was a challenge and very few software applications were available.

Nowadays this is still true. Firefox is still a champion of Open Source, it still proudly promotes Free Software outside of our community and it still produces one of the best and the most open browsers available not only to us but to millions of people who enjoy it on proprietary operating systems before migrating to Linux.

It’s a real pleasure for us to join forces with Mozilla and to start this partnership.

Changes in Firefox

Firefox will continue to be distributed as .deb packages through the official Linux Mint repositories. Its configuration and the way it is built is changing to make the Linux Mint version of Firefox much more similar (almost identical in fact) to the version which is distributed by Mozilla.

In the past Linux Mint used its own default settings and configured Firefox in a specific way. Most of this configuration is abandoned to go back to Mozilla defaults.

  • The default start page no longer points to
  • The default search engines no longer include Linux Mint search partners (Yahoo, DuckDuckGo…) but Mozilla search partners (Google, Amazon, Bing, DuckDuckGo, Ebay…)
  • The default configuration switches from Mint defaults to Mozilla defaults.
  • Firefox no longer includes code changes or patches from Linux Mint, Debian or Ubuntu.

For Mozilla, the goal is to make Firefox work the same way across all platforms to ease maintenance and simplify development and bug fixing. With these changes Firefox will give the same experience in Linux Mint as it does in other operating systems.

For us, this change means a tremendous simplification in terms of maintenance and development. We used to build Firefox ourselves using Ubuntu’s packaging (which is set to be discontinued as Ubuntu is moving towards snap). We now package the Mozilla version of Firefox instead.

With this partnership we also satisfy Mozilla’s requests when it comes to using their intellectual property (their name, brands and identity). For example, the Firefox icon is changing to follow Mozilla’s usage guidelines.

Frequently Asked Questions

Is this a commercial or a technical partnership?

It’s both. Thanks to this partnership it’s also much easier for us to communicate with Mozilla and to work with them on improving Firefox in Linux Mint.

In the past we added support for XApp window progress, which is the the ability to show progress in the Cinnamon panel window list when you download something with Firefox.

Better support for rounded corner in Firefox’s own window decorations is coming in Firefox 96.

We’re hoping to work with Mozilla on software updates in 2022, to make it easier for Firefox and the Update Manager to work together and for users to be able to see and apply browser updates straight from the browser itself.

When is the Firefox transition to Mozilla settings taking place?

In Linux Mint 19.x, 20.x and LMDE the transition is taking place with Firefox version 96, and it is planned for January 11th – January 12th.

In Linux Mint 20.3 the transition took place during the BETA with Firefox version 95.

Will the transition change “my” settings?

Technically and ideally, no. Preserving user settings is key. It’s a very important notion in software development and it’s taken very seriously both by Linux Mint and by Mozilla.

Changes to the default settings can however have an impact on your experience, since your settings are basically a layer of changes (overwrites) on top of the default values. As the default values change, any setting which isn’t overridden by a user value can indeed trigger a behavior change.

I added Google as my default search engine, will it still be there?

Yes, your default engine will continue to be Google. The only change is that it no longer will be a user added engine, it will be considered (and replaced by Firefox) as a system core engine.

I used Yahoo/DuckDuckGo/StartPage as my default search engine, will it continue to be my default?

No, these were core engines in the Linux Mint configuration. They no longer are present in the Mozilla version of Firefox. The default engine will switch to Google. DuckDuckGo will remain available but with a different URL (it’s a Mint search partner in the Mint configuration, but only a Mozilla partner in the Mozilla configuration).

Which search engines generate an income for Linux Mint?

In Firefox the only engine which generates an income for Linux Mint is Google.

In other browsers the only engines which generate an income for Linux Mint are Yahoo, DuckDuckGo and Startpage.

Will the transition negatively affect performance?

No. In fact we’re getting slightly faster performance with the transition.

Bug Reports

My version of Firefox looks wrong in the About dialog…

Note that “mint-001” and “1.0” are not the version of Firefox. They don’t relate to the packaging version either. They just represent identifiers of Linux Mint within Firefox.

The version of Firefox appears lower, “95.0.1” in this screenshot.

Firefox says it’s being managed by my organization

In Linux Mint the Update Manager is responsible for all software updates, and applying updates requires root privileges.

Your browser is being managed by your organization” might look a bit scary but all it means is that Firefox was told to not worry about updating itself.

In the About dialog, “Updates disabled by your system administrator” has the same meaning.

We’ll work with Mozilla on this, first to rephrase this, and hopefully later this year to be able to handle Firefox updates from within Firefox.

Where can I report bugs I find?

You can report bugs directly to us at

Or upstream to Mozilla at

When reporting a bug please include the output of the following terminal commands:

dpkg -l firefox*
dpkg -l ubuntu-system-adjustments

This helps us understand what language you’re using, and to see what relevant packages and versions are installed so we can reproduce issues and troubleshoot them.