Select your operating system ( win32/ , win64/ , linux/ , mac/ ). Choose your language (e.g., en-US/ ). Download the .exe , .dmg , or .tar.bz2 installer. 2. Third-Party Repositories (Use Caution)
Do you require a specific legacy like Java, Flash, or Silverlight?
Whether you need help on the same computer. Share public link
Legacy versions of Mozilla Firefox—specifically spanning from Firefox 12 up to Firefox 52 Extended Support Release (ESR)—remain highly sought after by system administrators, retro-computing enthusiasts, and developers. While modern browsers offer superior security and speed, these specific archival versions are critical for maintaining compatibility with legacy web applications, older operating systems, and deprecated web technologies. Download Firefox 12-51 52 Esr
For daily browsing, it is always recommended to use the latest stable version of to ensure your data and privacy are protected. run multiple versions of Firefox simultaneously using the Profile Manager?
Downloading outdated software carries inherent security risks. Third-party mirror websites frequently bundle old browsers with malware, adware, or tracking cookies. Always pull files directly from official repositories.
Never use legacy versions to log into banking portals, personal email accounts, or sensitive corporate infrastructure. Select your operating system ( win32/ , win64/
Mozilla previously maintained an FTP server ( ftp.mozilla.org ) with all older releases, but this was shut down in 2023. You can still access an unofficial mirror or use the Internet Archive's Wayback Machine .
Click the folder corresponding to the version number (e.g., 12.0/ , 45.0/ , 51.0.1/ ).
52.9.0esr is the absolute final version of Firefox supported on Windows XP and Windows Vista. Where and How to Download remote code execution
Many internal corporate tools, intranet portals, and database interfaces were built specifically around the rendering engines of older Firefox versions and have not been modernized.
Using outdated browsers introduces severe security vulnerabilities. Firefox 12 through 52 lack patches for hundreds of publicly documented exploits, rendering the system vulnerable to drive-by downloads, remote code execution, and credential theft. Best Practices for Risk Reduction
Firefox 52 ESR was uniquely configured to support NPAPI plugins while the standard rapid-release version of Firefox 52 dropped them entirely (with the temporary exception of Adobe Flash). For systems controlling industrial machinery, older routers, security cameras, or legacy financial portals relying on Java applets or Silverlight, Firefox 52 ESR is the definitive solution. The Last Stand for Windows XP and Vista