Download Firefox 12-51 52 Esr [best] May 2026

: Firefox 52 ESR was the final version to support classic "legacy" extensions ( XUL-based ). Many beloved power-user tools like Classic Theme Restorer or DownThemAll! (in its original form) only function on these older builds. Operating System Compatibility :

While newer versions like Firefox Quantum offer superior speed and security, these specific older versions are unique for several reasons: Download Firefox 12-51 52 Esr

Re-enabled non-Flash plugins temporarily and improved text input for third-party keyboards. : Firefox 52 ESR was the final version

Downloading and using old versions of Firefox is on the modern web. These versions: Legacy Add-on Support on Firefox ESR - The Mozilla Blog Download Firefox 12-51 52 Esr