Windows 10 may interrupt your Firefox install with a warning about "Microsoft-verified apps". Firefox is safe to install and use, so choose "install anyway".
Firefox automatically updates itself by default, but you can always do a manual update. Learn how to update Firefox on Windows, Mac, or Linux.
Firefox version 115 ESR will be the last supported release for Windows 7, 8 and 8.1.
Learn how to find out what Firefox version you are using, to help troubleshoot a problem or just to know if Firefox is up to date.
This article describes how to download and install Firefox on Windows.
This article explains how to download and install Firefox on a Mac.
This article describes how to download and install Firefox on Linux.
Firefox version 52.9.0 ESR was the last supported release for Windows XP and Windows Vista. No further security updates will be provided for those systems.
What to do if you spot fake notices claiming to contain an "urgent" or "critical" Firefox update.
You cannot install Firefox from Mozilla or from the Microsoft Store on Windows in S mode. You must first switch out of S mode. Learn more.
Firefox version 115 ESR will be the last supported release for macOS 10.12, 10.13 and 10.14
This article describes how to uninstall the Firefox application from your computer and also how to remove the personal information that Firefox stores.
The "Mozilla Firefox" app is available from the Microsoft Store for Windows 10 and Windows 11. Learn how to install it.
How to switch to Firefox ESR as a workaround for issues with the newest version of Firefox.
Downgrading to a previous Firefox version doesn't solve most problems. This article links to older versions and provides some alternatives.
Not sure whether you're running 32-bit or 64-bit Firefox on your Windows or Linux computer? This article explains how to find out.
If your bookmarks, passwords, preference settings and other data are missing, it may be available in another Firefox profile. Learn more.
Firefox and Thunderbird install Mozilla Maintenance Service to allow seamless background updates. Learn how it works and how to disable or remove it.
Firefox 78 was the last supported version for Mac OS X 10.9, 10.10 and 10.11. Users were moved to Firefox Extended Support Release (ESR).
On Windows 7, Microsoft update KB4474419 is needed to install Firefox 100 or above without any issues. Learn more.
Links to Firefox release notes for Desktop, Android and iOS.