The new Firefox design lands in today. This is what you can expect

[AshleyT]

Firefox has evolved significantly over the past year and now, its look has evolved too. 

The design begins rolling out today, with Firefox 157, bringing a cleaner, more cohesive , and more adaptable experience. It is still the Firefox you know and trust, with the same commitment to independence, privacy, customization, and user control. 

The Mozilla Connect community has helped shape this work from the beginning by sharing feedback on the early designs, tested the experience in Nightly starting in July, filed bugs, and shared with us what worked and what didn’t.

Here’s what landed today.

A cleaner, more cohesive design

• Softer tab shapes
• Redrawn icons that hold up better across light and dark themes
• Rebalanced spacing throughout the interface
• A refreshed color palette featuring the glow of the active tab, deeper purples, and warmer light tones

The updated design brought bolder color choices to Firefox — and your feedback made clear that opinions on browser color run the full spectrum. In response, we created additional themes, accessible through add-ons and a new theme picker off Firefox Home, so you have greater control over how Firefox looks. 

More ways to make Firefox yours

Firefox is becoming more customizable, giving you more ways to shape the browser around how you browse. These options include:

• A new theme picker in the customization panel on the Firefox Home page. Additional community themes remain available through about:addons.
• New Firefox themes and wallpapers
• A dedicated space to pin and organize shortcuts so sites you use all the time stay put.
• Compact Mode for a denser browsing experience

Compact mode now officially supported!

Compact Mode is now available as its own dedicated setting. It will also switch on automatically on smaller screens, reducing the space between interface elements so more fits on the screen.

This is one of the clearest examples of how community feedback shaped Nova. Many of you told us that maintaining a denser interface was important, and we listened.

Faster performance

The refreshed experience also includes improvements to Firefox’s startup, page-loading, and scrolling speeds.

Frequently asked questions

Will my existing themes and add-ons continue to work?

Themes and add-ons should continue to work. Nova is built on the same Firefox foundation, and the extension and theming architecture has not changed.

Will my userChrome.css customizations continue to work?

Some customizations may require minor adjustments, depending on how closely they rely on element names or layout structures from the previous interface. 

But keep in mind that Mozilla does not officially support customizations made through userChrome.css. They can cause unexpected behavior or even break Firefox, and future updates may affect them as Firefox continues to evolve. If you choose to use userChrome.css, please proceed carefully.

You can learn more in Firefox advanced customization and configuration options.

Can I opt out of the update?

The new Firefox design becomes the default experience starting with Firefox 157. However, you have several ways to adjust how Firefox looks and feels, including Compact Mode, themes, wallpapers, and New Tab customization. 

Keep shaping Firefox with us

Nova may be shipping today, but the work doesn’t stop here. Many of these updates grew directly from the bugs you filed and the conversations you started while the design was being developed.

Update to Firefox 157 to try the refreshed experience, then let us know what works well and what could still be improved. Your feedback will continue to help shape what comes next.

[eyilmazz]

We just want something simple and fast, yet we keep getting useless features; we don't want to switch to buttons with rounded corners that are much harder to click when there are many tabs open.

[cadwellm]

I just went to the ESR version and now I'm happy. Won't have to worry about FireFox crap for awhile.

[EmmaShev]

is there a portable vesion of ESR somewhere?

[dftf]

A website called PortableApps makes their own portable version.

The latest one can be downloaded here (click "Mozilla Firefox ESR, Portable Edition 153.4.0"):
https://sourceforge.net/projects/portableapps/files/Mozilla%20Firefox%2C%20Portable%20Ed./

Obviously you're trusting a third-party then not to have altered anything.  I'd recommend after downloading it, upload it to www.virustotal.com and do a scan of it before running it.

[jgrnt1]

I'm sorry, but ranting doesn't help anyone. It puts everyone on the defensive and hinders real conversation and progress. Rather than ranting about the rounded ends of the address and search boxes, I'd like to look at this from a functional UI standpoint. A text box is just that, a box. When I see rounded ends, I see a clickable button, not a place for text entry. Whenever I want to search something, I look at the top right of my browser for search entry and now I keep missing it, because the rounded ends instantly tell my mind I'm looking at a clickable button, rather than the search box. MS Edge uses a similar rounded ends text entry box, but their tabs are still actual tabs. Disabling Nova helps. 

[leojth]

In dark mode, the active tab is also black, which not signals "active" to me. Very confusing if only a few tabs are open.

[EmmaShev]

Oh gosh this new design looks so bad. Looks like something from the 2010s. It's so ugly

[dftf]

For now, you can reverse most of it:
URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

You can also install the previous theme here:
https://addons.mozilla.org/firefox/addon/firefox-proton/ 

⚠ The ability to reverse Nova may end in Firefox v161, expected Nov 24, 2026

[Jankcow]

Please add a way to disable the rounded edges!

[dftf]

To reverse most of the recent change:
URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

[Seacat17]

Make it LESS round please?

[dftf]

You can reverse most of the recent change (for now):
URL bar -> about:config -> ENTER -> accept warning -> search nova ->
double-click line "browser.nova.enabled" to change to "false"

[JNavas]

I appreciate that you are trying to improve Firefox, but your rapid pace of development is destabilizing. You need to slow the pace of development to consider changes more carefully and not ram them down our throats. And you need to do a much better job of quality control. You are destabilizing the browser. It works less well on multiple websites now than it did just a few months ago. You are in danger of losing my participation and support entirely. "If it ain't broke, don't fix it!"

[dftf]

As per my other reply to you: move to the ESR 153.4.0 release.

The ESR ones last for around a year, and only get security-updates in that time;
they don't get new features, or UI changes.

You might find it suits your needs better, especially given the regular releases of
Firefox are switching to one major new version every two weeks soon!

[emmaharris]

This is a total step backwards and you are becoming more and more like Chrome. I want to REMOVE Google, Bing etc from the search engines yet you have now disabled that. You default AI features ON when I explicitly turned them off. 

[JNavas]

The new leadership at Mozilla is trying to reverse the decline in market share, and is adopting the Google approach of a new UI design. Unfortunately, that will probably fail because UI is not the reason most users are abandoning Firefox. Worse, the new UI is unlikely to attract new users (who prioritize functionality).

Mozilla will only be able to stop the slide if it remedies core functionality issues that are driving users away, but instead these changes are making those issues worse.

When I have to switch to Edge to make a website work properly, eventually there will come a time when I won't be switching back to Firefox.

In the meantime, the best solutions:

• Revert to the last good version and stop updating.
• Switch to the ESR version and stop updating.

[dftf]

---

In the meantime, the best solution is to revert to the last good version and stop updating, not to rely on temporary switches.

---

No, going back to 156 and then turning updates off is unsafe; move to the 153.4.0 ESR version instead, as that predates the Nova UI, but gets security-fixes for around a year from now.

Download it here: https://www.firefox.com/download/all/desktop-esr/ 

Then backup your current data (bookmarks, passwords, history, etc) first:
Menu -> Settings -> Accounts and Synchronisation -> Backup

Then uninstall 157, reboot your PC, then install the 153.4.0 ESR.

If your data isn't there in the ESR version, recover it from the backup you did earlier:
Menu -> Settings -> Accounts and Synchronisation -> Restore your data

[JNavas]

You do not need to uninstall the standard version before installing the ESR version in a copy of your Profile. You should wait on the uninstall until after you have completed the transition.

[dftf]

This may cause issues, as in recent versions of Firefox profiles from newer versions cannot always be imported into older ones.

There is a command to allow this (--allow-downgrade), but it's easier just to advise doing a backup, uninstalling, installing the ESR then re-importing, if needed.  The backup then allows for recovery, should the profile not be there.

[ghzorqie]

@AshleyT wrote:

Firefox has evolved significantly 

This is an ape with a haircut, not evolution.

[WaGi-Coding]

Eww, i'll download another browser now, you keep ruining Firefox with every update more and more

[dftf]

You could try a "fork" of Firefox, such as:
Basilisk • Floorp • Librewolf • Pale Moon • Waterfox

Or backup your current Firefox data (Menu -> Settings -> Account and Sync -> Backup), then uninstall 157, reboot your PC, and install Firefox ESR 153.4.0.  Then you'll avoid the new UI for about a year.  If your data isn't there in the ESR, use Menu -> Settings -> Accounts and Sync -> Restore your data.

Download the ESR here:
https://www.firefox.com/download/all/desktop-esr/ 

[JNavas]

> uninstall 157, reboot your PC, and install Firefox ESR 153.4.0

A better solution is to install ESR on a copy of your Profile without deleting the standard version until after you have completed the transition to ESR.
When installing ESR, select Custom and then change the Install Folder to something like 'Mozilla Firefox ESR'.

[dftf]

You can have the standard, ESR, beta, developer and nightly all installed side-by-side should you wish, absolutely.

Be aware though support for undoing Nova is currently set to be removed in Firefox 161, due for release Nov 24th (see: https://bugzilla.mozilla.org/show_bug.cgi?id=2071454 ), so after that time the stable-channel version may not be an option for those who really dislike the new UI.

Outside of the ESR, the only other options at that time would be a Firefox "fork", such as:
Basilisk; Floorp; Librewolf; Pale Moon; Waterfox

Though some of those may decide to only offer Nova too at that point, as otherwise they will have to maintain the code for the old UI themselves, and may decide it too-much effort.

[gz3xzf]

I have been a faithful user of Firefox for over 10 years, now I am now looking at other independent browsers to use.

Version 157 appears to have a memory management issue, when I run Firefox (one window with one tab) the memory usage on the computer bounces between 50% & 96%, when it's at over 90% the Windows system is trashing disk 0 paging; during this time the computer stops responding.
I am currently using Microsoft Edge as an alternative until I find a secure alternative browser or Moz://a patch/update Firefox.

[gbjbaanb]

Edge? Jesus man, don't do this to yourself,.

Try Vivaldi, its been mentioned a lot in these forums.

[JNavas]

> Edge? Jesus man, don't do this to yourself,.
> Try Vivaldi, its been mentioned a lot in these forums.

Thank you, but I keep up with all the significant desktop browsers, and:

• I prefer the functionality and performance of Edge over Vivaldi.
• I have no use for the unique Vivaldi features.

Firefox has been my recent daily driver because it:

1. Still supports MV2 (important to me as an extension developer and user).
2. Has good support for extensions on Android (same as above).
3. Has good integration between Windows and Android.
4. Had decent support for most websites.
5. Had a decent UI without the silly changes afflicting other browsers.

Firefox nearly lost me when it sold out to Comcast on DNS, and now that #3 is eroding, #4 is gone, and Edge is starting to support extensions on Android, my remaining days on Firefox (even ESR) are probably numbered. It's a shame, because the Internet needs a successful Firefox.

Sic transit gloria mundi.

[dftf]

You could always move to the 153.4.0 "ESR" version of Firefox, which predates the new Nova UI and doesn't get new features or UI changes for around a year, but still gets regular security-updates:
https://www.firefox.com/download/all/desktop-esr/ 

You should backup your current data (bookmarks, passwords, history, etc) first:
Menu -> Settings -> Accounts and Synchronisation -> Backup

Then uninstall 157, reboot your PC, then install the 153.4.0 ESR.

If your data is missing in the ESR version, just restore it from the backup you did earlier:
Menu -> Settings -> Accounts and Synchronisation -> Restore your data

[Telemaker]

It is  disgrace that they did not themed, this so called "update". I am not gonna add to all the clever things already said but.....Oh my....How much i hate rounded border, buttons, tabs, and everything........

If this is the direction....guys you are loosing it.

Perfeormance is what we want.

The question was in a long time forgotten song "Is ther anybody out there?"

[Ghostty]

I personally find the new design painful to look at - it looks like "corporate art". Why round every corner? the main reason I even switched to mozilla was because others became too flashy. I as an IT nerd love simple looks and thats how (in my humble opinion) every core of the app should look. Why the rounded tabs? why the gradient outlines? why the funny oversized ROUND (again) tab groups? All of these should be optional, all of these could be themes... This will sound ridiculous but I nearly cried after mozilla updated itself on my PC as I've been actively avoiding the new look since first noticing it on my laptop. Incredibly disappointing...

[JNavas]

Thank you! Thank you! Thank you! 
You prompted me to switch back to Firefox ESR, and it's like a breath of fresh air!
It was more hassle than it should have been—manually rebuilding the Home page was a real PITA—but I did take the opportunity to clean up cruft.
It's a welcome return to clean UI and stability.

[cadwellm]

I'm also glad I went to the ESR version. It looks so...normal. And it's nice to no it won't be changing every other week.

[lunaria]

The Nova redesign significantly reduces the legibility of the tab bar, especially with container tabs.

For reference, here is a row of tabs with Nova:

And here is the same row without Nova:

1. Notice that with Nova, the container tab color bar crowds the text and makes it more difficult to read.
2. Additionally, with Nova, there is less contrast between the background color of the active tab and the color of the rest of tab bar + inactive tabs, making it more difficult to see which tab is active at a glance. It seems that Nova intends the user to tell which tab is active via the new colored border around the active tab, which requires interpreting important UI information via hard-to-notice fine details.
3. When the active tab is a container tab, these problems compound each other. The active tab outline, the container tab color bar, and the tab title text all crowd into each other to form an illegible visual soup.

Beyond being ugly, the redesign makes the UI significantly less legible, both in terms of design legibility and in terms of the literal readability of the test. This does not feel like a browser designed to be used by humans.

[lunaria]

Also, just a more general comment: You will never, EVER, get people to switch from Chrome to Firefox by making Firefox more like Chrome. People who want a browser like Chrome already have a browser like Chrome, it's Chrome. Turning your browser into a knockoff of other, more popular browsers will only hasten its irrelevance.

[cadwellm]

Wish I could give this more than one thumbs up!

[dftf]

To be fair, if you go back to the "Australis" era, that's when they really-did try to mimic Chrome:
https://github.com/black7375/Firefox-UI-Fix/wiki/%5BArticle%5D-0.-Firefox-UI-UX-history#australis-v2... 

The current Nova UI is macOS-like which is fine... when used on macOS.
But looks odd on Windows and many Linux DEs.
But I'd imagine all their internal US-based staff use Macs, so... they go with what they know.

[Jonisjalopy]

I took the time to log into the forum just to add my dislike for this new "Nova" look. If you indeed go through with removing the option to disable it in an upcoming build, I will stop using the browser and find one that doesn't look so terrible. Please reconsider this design change.

[dftf]

The option to reverse Nova is set to be removed from Firefox 161, due Nov 24th

You could consider moving to a "fork" of Firefox, such as:
Basilisk , Floorp , Librewolf , Pale Moon , Waterfox

Or switch to the 153.4.0 "ESR" release, which gets security updates for about a year from now, but no new features or UI changes (and it predates Nova, so that's not there).  You can download it here:
https://www.firefox.com/download/all/desktop-esr/ 

[Agentvirtuel]

Bonjour

This information https://support.mozilla.org/en-US/kb/understanding-depth-profile-installation
https://support.mozilla.org/en-US/kb/dedicated-profiles-firefox-installation#w_what-happens-to-my-pr...

About the compatibility.ini file.
What happens to my profile if I downgrade to a previous version of Firefox?
For illustration https://www.youtube.com/watch?v=LVKibALFaB4

[Aosha]

Gonna be honest, the visual update is a miss. The rounded tabs especially are a big enough downgrade I'm thinking of switching browsers. The other bits... some are fine, most I can *live with*, but the tabs are just inexcusably bad. Thankfully I can still revert that, but if the option to do so goes away, I'm also gone.