While Mozilla generally recommends using the latest version of Firefox for security, there are times when you might need to download an old version—such as for testing legacy web applications, supporting older operating systems, or recovering a specific removed feature. Where to Download Old Versions of Firefox
| You want version… | Go to folder | Download file example | |---|---|---| | Firefox 56 (classic pre-Quantum) | /pub/firefox/releases/56.0.2/win64/ | Firefox Setup 56.0.2.exe | | Firefox 52 ESR | /pub/firefox/releases/52.9.0esr/win64/ | Firefox Setup 52.9.0esr.exe | | Firefox 3.6 | /pub/firefox/releases/3.6.28/win32/ | Firefox Setup 3.6.28.exe | download old version firefox
: Select win32/ or win64/ for Windows, mac/ for macOS, or linux-x86_64/ for Linux. While Mozilla generally recommends using the latest version
While sites like OldVersion.com host older files, it is generally safer to stick to official sources to avoid tampered installers. Step-by-Step Installation Guide Only use them for testing legacy websites, web
Firefox includes "downgrade protection" to prevent newer profile data from corrupting an older browser. To bypass errors or data loss, follow these steps:
Do download from random third-party sites. Use official or well-known repositories:
Older Firefox versions have unpatched security vulnerabilities . Only use them for testing legacy websites, web development, or running old extensions. Do not use them for everyday browsing (banking, email, logging into accounts).