Firefox 140 hits the wilds today, an update focused more on refinement and finesse for its existing feature set than adding any major new ones.
Not that is just a regular monthly update. Firefox 140 is also the new Extended Support Release (ESR), meaning those who opt for the slower, more stable upgrade pace ESR provides will see a significant uplift in features available to them.
For monthly folks, there are appreciable improvements to look for, including tweaks to the vertical tabs experience, an easier way to free up memory from background tabs, more flexibility for search engines, and a dampening down of ‘visual noise’ on the New Tab page.
To take a closer look at this month’s changes, read on!
Firefox 140: What’s New?
Vertical pinned tab resizing
Of all the features Firefox has (belatedly, in many cases) added of late, vertical tabs is the one which has attracted the most positivity from comments below the line.
This feature has seen a couple of iterative improvements since its debut, and the latest update makes another: the “pinned tabs” zone in vertical tabs layout is now resizeable.
In icon/collapsed mode, drag the divider beneath the pinned tabs section down to see more pinned tabs in view, or drag it up to have fewer pinned tabs on show. In expanded mode, drag the divider right/left respectively.
Free up memory from inactive tabs
If you have a lot of tabs open and system memory starts running low, Firefox is able to unload inactive tabs to free up resources — this happens automatically, in the background.
Firefox 140 sees an ‘Unload Tab’ option added the tab strip context menu. This lets you quickly free up memory and reduce CPU usage for any tab (or multiple selected tabs) anytime you like.
One thing to note: unloading a tab doesn’t close the tab, it just stops it running in the background until next focused at which point it will load.
An unloaded tab is kind of like a ‘temporary bookmark’, in a sense.
Custom search engines
This update makes it much easier to add custom search engines in Firefox. You can now right-click in a search field on a supported website and select “Add Search Engine” to add it. You can edit the name and assign a keyboard.
Alternatively, go to Settings > Search > Add and manually enter your custom search engine by filling out the various fields. Again, you can add a keyword to make using your custom search engine easy by typing @keyword in the URL bar.
Other changes
For some users, recommended and sponsored stories on the New Tab page no longer show descriptive text blurbs. Mozilla say this change will “reduce clutter and visual noise” and is “part of an ongoing effort to refine the look and feel” of the New Tab page.
Firefox’s “on-device” web page translations are handy, if slow. To speed ’em up (and reduce resource usage) Mozilla has made full page translations only translate content on show with content behind translated when you scroll to it.
If you install a lot of Firefox extensions (aka ‘add-ons’) you may find the extensions menu shortcut shown in the toolbar useful (it’s where unpinned add-ons live).
But if you don’t install many Firefox extensions, it’s “visual noise” – so you can finally remove the toolbar extensions icon in Firefox 140: right-click > Remove from Toolbar1.
Beyond what’s spotlighted above, other changes in Firefox 140 include:
- Sponsored suggestions in the address bar now shown in UK
- Built-in Arabic dictionary for Firefox spellchecker (Arabic locales only)
- Pocket toolbar icon and New Tab integrations removed
- Linux theme changes (new titlebar buttons; GTK theme rendering removed)
- Local AI models can be viewed on
about:addonspage - Support for aria-keyshortcuts
- CookieStore API support
- Custom Highlight API support (text-decoration not supported yet)
- Service Workers are available in Private Browsing Mode
Plus, the usual assembly of security fixes to ensure we’re all browsing safely.
In all, another welcome set of improvements that further fill out this stalwart of the free and open source software scene. Steady, iterative updates are part of the reason many favour Firefox over Chromium-based rivals.
Let me know what you think of this latest crop of changes by leaving a comment!
Firefox 140 ESR
Okay, it’s a double-whammy this month as Firefox 140 is also the new ESR release.
For those favour stability and predictability over shiny new-new-ness and feature churn, Mozilla Firefox ESR is recommended. It gets one major ‘feature’ release a year, but scores of security and bug fix updates in between.
Firefox 140 ESR replaces Firefox 128 ESR, which launched back in July 2024. Since it rolls together a year’s worth of changes, ESR users get to enjoy features that monthly users have had for some time, including:
- Tab grouping
- Vertical tab layout option
- New Firefox sidebar with third-party AI chatbot access
- Tab preview shown when hovering over a background tab
- Option to translate selected portions to different languages
- Improved Reader View with new text, layout and theme options
- Web addresses in PDF files auto-convert to clickable links
- Links can be copied from background tabs without focusing them
- Various Enhanced Tracking Protection tweaks
- “Copy Without Site Tracking” renamed to “Copy Clean Link”
- Touchpad hold gestures enabled on Linux
- Text fragment support
Beyond that, Mozilla has made a couple of tweaks to ensure that enterprise deployments of ESR (the primary use-case) are “easier and even more flexible”.
However, existing users of Firefox 128 ESR will not be auto-upgraded to the new v140 based for a few months, likely near the release of Firefox 140.3 ESR in September.
Download Firefox 140
If you use Ubuntu with the Firefox snap installed the latest Firefox release will be installed automatically, in the background, without you needing to do anything, as of today (June 24). Look out for a notification to tell you when to restart the browser to apply the update.
If you use Linux Mint you can update to Firefox 140 via the Mint Update tool, as Firefox continues to be provided as a DEB package updated via APT.
If you’re using Ubuntu and you don’t have Firefox installed, but want to, you’ve plenty of choices: use the official Snap or Flatpak build; add the Mozilla APT repo to install a Firefox DEB; or download a distro-agnostic Linux binary from the Mozilla website directly.
- In an earlier release of Firefox the ‘remove from toolbar’ option was present but greyed out. ↩︎