Firefox automatically updates itself by default but you can always do a manual update. Learn how to update Firefox on Windows, Mac or Linux.
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".
This article describes how to download and install Firefox on Windows.
Firefox version 52.9.0esr was the last supported release for Windows XP and Windows Vista. No further security updates will be provided for those systems.
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 will show you how to install Firefox on Linux.
This article explains how to download and install Firefox on a Mac.
Windows 10 S Mode can only run applications downloaded from the Windows Store.
If your bookmarks, passwords, preference settings and other data are missing, it may be available in another Firefox profile. Learn more.
Downgrading to an older Firefox version doesn't solve most problems. This article links to older versions and provides some alternatives.
Firefox 78 is the last supported version for Mac OS X 10.9, 10.10 and 10.11. Users will be moved to Firefox Extended Support Release (ESR).
This article describes how to remove the Firefox application from your computer and also how to remove the personal information that Firefox stores.
Firefox and Thunderbird install Mozilla Maintenance Service to allow seamless background updates. Learn how it works and how to disable or remove it.
Not sure whether you're running 32-bit or 64-bit Firefox? This article explains how to find out.
Firefox version 49 and above are no longer supported on Mac OS X 10.6, 10.7 and 10.8. Learn more about your options.
What to do if you spot fake notices claiming to contain an "urgent" or "critical" Firefox update.
How to switch to Firefox ESR as a workaround for issues with the newest version of Firefox.
How to make sure you're using the Apple Silicon version of Firefox.
Links to release notes for Firefox and Firefox for Android.