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Firefox ESR means Extended Support Release. It is a Firefox edition that keeps a major feature base for longer while receiving security updates. Regular Firefox is usually the better choice if you want new browser features sooner. ESR mainly helps organizations and people who need a slower pace of major changes.
ESR is not an excuse to stop updating. An outdated ESR release can lose support, just as an outdated regular release can.
Firefox versus Firefox ESR
| Question | Regular Firefox | Firefox ESR |
|---|---|---|
| How do new features arrive? | Through the regular release cycle. | Mainly when the next major ESR base arrives. |
| Does it receive security fixes? | Yes, while the release is supported. | Yes, through supported ESR maintenance updates. |
| Who is it aimed at? | Most everyday browser users. | Organizations and users needing fewer major changes. |
| Can anyone download it? | Yes. | Yes; a business account is not required for the public download. |
| Is it automatically faster or more private? | The release label alone does not prove either claim. | |
What changes less often in ESR?
A major ESR branch holds its feature base longer than the regular release. That gives an organization time to test important websites, internal tools and managed settings before a larger browser change.
Mozilla’s ESR release-cycle guide says ESR branches are maintained for more than a year and describes an overlap when a new branch arrives. Maintenance focuses on important security fixes; it does not bring every regular Firefox feature back to the older base.
A lower-looking ESR version number therefore does not automatically mean it is unpatched. Check whether that exact ESR branch is supported and fully updated. Conversely, seeing “ESR” in the name does not make an abandoned branch safe.
Which edition should you choose?
- Choose regular Firefox for normal home browsing unless you have a clear reason to use ESR.
- Consider ESR when you need to test and manage browser changes more slowly.
- Follow your IT team’s choice on a managed computer. Changing editions yourself can interfere with its setup.
Do not choose ESR just to avoid a security update or keep an unsupported add-on alive. Also avoid treating it as a special privacy mode: privacy depends on settings, extensions, websites and keeping the browser maintained.
Download and check your edition
- Use Mozilla’s official Firefox ESR page or the normal Firefox download page.
- Choose the operating system, language and architecture that match your computer.
- After installation, open Firefox’s menu and choose Help > About Firefox.
- Read the version and edition, and allow any available update to finish.
If a listing says x64 en-US, x64 refers to the 64-bit build and en-US to US English. Those labels do not describe a separate type of ESR. For help checking a Windows PC’s system type, see System Properties and the About page.
Can regular Firefox and ESR be installed together?
Separate installations are possible. Modern Firefox uses dedicated profiles for different installations, as Mozilla’s profile guide explains. It is inaccurate to say that only one edition can ever be installed.
Keep the installations and their profiles separate. A profile contains bookmarks, history, settings and other browser data. Back up important data before changing editions, and do not force an older browser to reuse a profile created by a newer one.
If your main aim is to change what opens when the browser starts, you do not need to switch editions. See our homepage and startup settings guide.
Common questions
Is ESR the same as an old Firefox installer?
No. A supported ESR branch has its own maintenance updates. An arbitrary old Firefox installer may have neither current fixes nor support.
Can Chrome Web Store extensions be added to Firefox ESR?
Not through the store-install process used by Chromium browsers. If you use Microsoft‘s browser instead, our Chrome extensions in Edge guide covers that separate route.