Firefox 142 ships with Tracking Protection, Tab Groups, and Extensions improvements
Mozilla released Firefox 142 Stable as well as various supported Firefox ESR (Extended Support Release) updates today. Mozilla introduces quite a few changes in Firefox 142 that improve the usability. Highlights include new options for tab groups, tracking protection, and new features for extensions.
Firefox 142: the major changes and new features
Tracking Protection Exceptions
Tracking Protection is a privacy feature that blocks certain forms of tracking and may also improve the page loading time. However, issues on certain websites may be experienced at times when the feature is enabled.
Mozilla is introducing a new exceptions feature for Firefox's Tracking Protection to avoid "major website breakage". Note that this applies only to the strict level of Tracking Protection in Firefox.
Here is how you configure it:
- Load about:preferences#privacy in the Firefox address bar.
- Scroll down until you come to the Tracking Protection section.
- With Strict enabled, check or uncheck "Allow Firefox to automatically apply exceptions required to avoid major website breakage"
- Optional: Check "Also apply exceptions automatically that are only required to fix minor issues and make convenience features available".
- Activate the "Reload all tabs" button to apply the changes.
The active tab stays visible in Tab Groups, even if you collapse the group
Tab Groups are a recent addition to Firefox. They improve management of tabs. Starting in Firefox 142, Firefox keeps the active tab visible in a Tab Group, even if you collapse it. The tab shows the active tab as usual in the group while the other tabs of the group are hidden.
Firefox displays a number next to the active tab to indicate the number of hidden tabs.
Other changes and fixes
- Link Previews is rolling out. Long-press a link or right-click on it and select Preview Link, to get a preview of the linked resource, without opening it directly. The feature is rolling out to the locales en-US, en-CA, en-GB, and en-AU only at this point. Also, Mozilla notes that it is only available of more than 3 GB of RAM is available.
- Extensions can be removed from the sidebar now by right-clicking on them and selecting "Remove from Sidebar".
- Extensions may access local AI models. This allows developers to integrate AI features using local models going forward.
- Users from the United States will see article suggestions grouped by topics such as science, health, or travel on the browser's new tab page. Options to follow or block certain topics are also available.
- Mozilla improved search results from the browsing history. This should reduce "the likelihood of duplicate results" according to the release notes.
- Clicking a persistent notification on Windows while Firefox is closed/restarted will open Firefox with the relevant webpage properly now instead of the main page of the website.
Developer changes
- The <object> element no longer supports the deprecated codebase attribute. Use the data attribute instead.
- The URL Pattern API is fully supported.
- The Selection.getComposedRanges() method is now supported.
- The Animation.overallProgress property is now supported.
- The Animation.commitStyles() method no longer requires fill to be set on an animation to commit the computed styles after the animation has finished.
- The Prioritized Task Scheduling API is now supported, providing a standardized mechanism to assign and manage task priorities for an application.
- The currentRoundTripTime, totalRoundTripTime, and responsesReceived properties of the RTCIceCandidatePairStats dictionary are now supported.
- The setParameters() and getParameters() methods of the RTCRtpSender interface now support setting and getting the specific codec used for each encoding.
- The estimatedPlayoutTimestamp, framesAssembledFromMultiplePackets, freezeCount, jitterBufferMinimumDelay, jitterBufferTargetDelay, keyFramesDecoded, pauseCount, totalAssemblyTime, totalFreezesDuration and totalPausesDuration properties of the RTCInboundRtpStreamStats interface are now supported..
- Cookies created with cookies.set() in Nightly are now validated, and invalid cookies are rejected.
Enterprise changes
- Permissions policy was updated to allow the configuration of permissions for screen sharing.
- The EnableTrackingProtection policy supports setting the feature to strict or standard. When set, users can't change it. Also, you may use it to control Suspected Fingerprinters.
Security updates / fixes
Mozilla patched a total of nine security vulnerabilities or potential security issues in Firefox 142.0. The aggregate severity rating is high and Mozilla makes no mention of exploits in the wild.
Firefox 142.0 download and update
Most Firefox installations should be updated automatically today and in the coming days. You can check the installed version by selecting Menu > Help > About Firefox.
Manual downloads are also provided on Mozilla's official website for desktop operating systems.
Outlook
Firefox 143.0 will be released on September 16, 2025. There is one more planned release of Firefox 128 ESR, after which it will go out of support. Firefox ESR installations will be updated automatically to Firefox 140 ESR afterwards.
Mozilla has yet to make a decision regarding Firefox 115.x ESR. A decision will be made by next month.
Additional information / resources
A very good version IMHO, however Firefox 142 was updated from Italian to English in Ubuntu 24.
Users may receive the error “You’ve launched an older version of Firefox” and it will offer two options–“Exit” or ” Create new Profile.” I haven’t found any way to avoid creating a new profile, so I didn’t update to the latest, greatest ESR version.
You can modify the version in “%AppData%\Mozilla\Firefox\Profiles\\compatibility.ini”, or you can run Firefox with the –allow-downgrade switch
Thanks–a couple of methods worked.
1. Run the command firefox -allow-downgrade–then, update.
2. Backup profile; create new profile; run firefox -p and browse to old profile [backup]. All extensions, bookmarks, etc. intact.
3. I did find the comaptability.ini file in my current profile, but was unsure of what version to change it to.
https://superuser.com/questions/1791613/ff-error-youve-launched-an-older-version-of-firefox-and-changes-that-reall
And quietly adding “sponsored stories” to the home page (which can be disabled).
I am patiently waiting for them to add mkv support.
“We are in the transition period between major ESR versions 140 and 128.”
Any news on the above? FF updated today; the version went to 128.14. On a different computer, the version took a leap to 140 and required a new profile. It was sort of a mess.
How will Mozilla roll this out to numerous users without everyone losing the old profile and all that entails?
Always the same mess with the profiles… They always learn nothing.
I remember many years ago, when I was still using Firefox, I wasn’t doing anything, using the regular version, not ESR and quite often whether Firefox gets updated or not, there would be a profile error, I didn’t know how to fix it, so I just started anew. But later I couldn’t stand it anymore and it was one of the reasons I moved away from Firefox for good.
I believe this error became more prevalent after version 4.x of the browser released. Firefox 3.x was more stable and in my opinion the last good version of Firefox, after that it’s been a joke that the developers try to make funnier with every update, but nobody is laughing anymore, because the joke is long dead.
I forgot to mention, I see two paths going forward with Firefox:
1. It eventually loses so many users in the next 2-3 years that Browser Market Share charts fail to even detect it and put it into the Other category and then it gets shut down after a while, because it’s not feasible to maintain it.
2. Firefox adopts Chromium and the Blink rendering engine (or maybe WebKit if they are anti-Google, but I doubt Google will keep sponsoring its existence if they move to WebKit) in a hope to survive and become a more relevant browser.
I could be wrong, of course on both accounts, but there have been proclamations by Firefox fans for the last couple of years “when Chrome disables Manifest V2, everyone will move to Firefox”, well, that time has come and gone and so far nobody has moved to Firefox.
Firefox 4.0 was released in 2011, so you’ve been repeating your lament about it being the last good version for 14 years. You stopped using Firefox long ago, yet you continue to comment in this forum about Firefox as though you know how it works. Can you explain?
Also, you say you think Firefox should try to “become a more relevant browser.” How would it do that? And I’m talking about features or stability that a regular browser user would see and appreciate, not the “in the weeds” topics that are typically discussed in this forum.
I’m really interested to hear your thoughts on this, Allwynd. I’m not being snarky. Thanks.
Google will sponsor Firefox with Gecko but not with WebKit? They already don’t use Blink, what would change?
@Allwynd, you could be wrong, indeed; I think you are, but I could be, wrong, as well :)
Who knows? Predictions nowadays are more unreliable than ever. Not only things move quickly but, because they move quickly, offer a too short perspective to elaborate a pertinent analysis in time. Just like with stock markets.
Concerning Chrome users who haven’t shifted to Firefox when Manifest V3 imposed itself, no need to remind that the majority of Google’s Chrome users isn’t really committed to privacy, most of it just needs a helping hand to be pushed or pulled towards the eldorado, an eldorado named Google. Majorities entertain democracies, not intelligence, nor creativity, nor initiative, they seek for comfort and assistance. Small is beautiful, so are minorities quite often. I’m always surprised of the relationship established between a product’s quality and its number of users, as if there were any.
Rock’n’roll at its beginnings was announced by some short-sighted analysts as a short-term phenomena, bound to quickly vanish; seven decades later, still alive. Firefox, as rock’n’roll is here to stay. Shake it, baby, shake it ?
May I ask what about the new ESR release required a new profile? Sounds worrisome :(
All sorts of information online for a manual copy, but Martin has an old article. I was trying to think of the programs he mentioned:
https://www.ghacks.net/2011/06/28/backup-all-firefox-profiles-with-a-batch-file/
MozBackup is easy enough to find; Batckup Firefox here–
https://www.softpedia.com/get/System/Back-Up-and-Recovery/Batckup-Firefox.shtml#download
That is a major reason why I am never in a rush to install the updates for anything–I wait a week after the release minimum and enforce that with WinPilot, unless there is something like a zero day situation, which does not happen that often. I see no need to go beyond Win10 22H2 for the forseeable future–0patch has the end of support situation covered to my satisfaction.
Hope reinstalling the backup does not also remove the good parts of the update along with it, essentially reverting to the previous release. Then getting the nags to update it again which you cannot turn completely off that I am aware of.
I am just going to do a Win system backup first , then the Firebox backup to be extra cautious.