Mozilla has released Firefox 153 with built-in containers, QR code generation and more quick actions in the address bar.
This is the final “monthly” stable release before Mozilla moves to a faster release cadence, putting out new stable versions of Firefox every two weeks. On an unrelated note, Firefox has decided to resume activity on X (formerly Twitter) after a year of no activity.
Like all updates, you can get this one for Windows, macOS and Linux, as well as for Android and iOS (mobile versions have different features and are not covered in this post).
Firefox gets built-in Containers
Containers are the biggest new feature in Firefox 153. These, Mozilla say, let you “separate cookies by container so you can use different accounts on the same site and limit cross-site tracking” between them.
Handy to, say, use both a personal and work social media account at the same time, in the same window, without needing to juggle different windows or install add-ons to avoid cross-contamination between accounts.
Mozilla’s offered container functionality for years through add-ons. In Firefox 153, core container functionality is built-in. Four preconfigured containers are setup by default, Personal, Banking, Shopping and Work, and you can add new containers yourself.
To use Containers in Firefox, right-click (or hold alt and click) on the new tab button and select a container. Or, right-click on an existing tab, mouse to “Open in Container tab” and select one there. Container tabs are colour-coded and show an icon in the URL bar.
If you really love containers, you can reduce the friction further by heading to the Containers settings page. There, you’ll find an option to have the containers menu open each time you press the new tab button.
QR codes and PDF buffs
If you want to share a website via a QR code (but find online QR code generators like bar.codes effort – Firefox lets you right-click a tab and select Share > Generate QR Code to make one. Just, y’know, use ’em for offline needs as clicking links online remains far easier.
Mozilla also continues to flesh out Firefox’s built-in PDF editing feature set.
The browser added PDF merging in May, but that relied on a file chooser to select the PDF to merge. In Firefox 153 you can merge by dragging a PDF into the sidebar. You can also add images as new pages, which is useful for adding document covers and diagrams.
Rounded corners on Linux
Eagle-eyed Linux users may notice Firefox flipped the switch on using rounded bottom corners for windows on GTK desktops, such as Ubuntu. You could manually enable this setting for years, but it is set to true by default – at least it is in the binary build I tried.
Other changes
Other changes in Firefox 153 include more quick actions in the address bar.
You can get to the Firefox Labs page if you type “labs” or “experiment” and click the “labs” action. To copy a colour from the web page you’re viewing, type “pick colour” or “eyedropper” in the address bar and use the “pick a colour” action to get an eyedropper.
If a website has permission to view your location, the browser now lets you know by highlighting the relevant icon in red so you know it’s active. This expands to search results pages where, per Mozilla, it was previously hidden.
On macOS, Firefox now supports Apple’s system-wide full-screen keyboard command (Globe + F), while Windows builds of Firefox 153 now support HDR video playback (where supported and enabled in Windows itself).
However, Mozilla note HDR won’t work on laptop displays that only support “HDR video streaming” at present, and says some videos shot on smartphones in certain orientations may continue to render in SDR.
The desktop build now supports the Picture-in-Picture API (not a user-facing change, per se), adds support for JavaScript text modules, and can display Qualified Website Authentication Certificates (QWACs) per eIDAS regulations.
All of that, plus the usual batch of bug fixes, optimisations and security patches.
Smart Window changes
If you’re testing Smart Window in Firefox, the browser’s new “AI mode”, you can pick a preferred AI model to power this error-prone feature straight from the Smart Window assistant.
And the New Tab now has a URL bar for typing website addresses and searching the web. Y’know, like a luddite would. This change rather makes me wonder what the point is… Isn’t that just Firefox, but with the AI chatbot on the other side?
Getting Firefox 153
Firefox 153 is available to download today, 20 July 2026, from the Mozilla FTP, or from the 21 July on the Firefox website. The update rolls to existing users from 21 July.
Ubuntu users will be upgraded via an automatic background update from the Snap Store, unless using another package format.