If you need a version that is no longer on the main Mozilla server, or if the FTP is slow, sites like or MajorGeeks often host archives.
Inside the version folder, you will see folders for different operating systems: download firefox old version
For a slightly more guided experience, the Mozilla Support "Install an older version" page contains links to major previous versions. Step-by-Step Downgrade Guide If you need a version that is no
Run the installer. You may be prompted to create a new Firefox profile because older versions often cannot read data from newer profiles. Critical Precautions and Risks Using an outdated browser comes with significant warnings: You may be prompted to create a new
Go to the official Mozilla release server: https://ftp.mozilla.org/pub/firefox/releases/
If you need to keep your modern Firefox but use an old version for a specific task (like legacy Flash content or testing), do not uninstall your current version. Instead, use .
[ Firefox 56.0.2 ] | Oct 9, 2017 • Last version with full XUL/legacy add-on support • ⚠️ 12 known security issues • Windows 7+ / macOS 10.9+ / Linux [ Download (52 MB) ] [ SHA256 ▼ ]