If you have landed on this page searching for the keyword , you are likely not looking for the newest Quantum engine or the latest UI overhaul. Instead, you need a specific piece of internet history.

If you install Firefox 52 ESR, you must immediately disable automatic updates. Otherwise, it will auto-upgrade to Firefox 60 ESR (which drops NPAPI support and will break your legacy plugins).

Always download directly from archive.mozilla.org . Never trust third-party "old version" websites, as they are notorious for bundling malware.

Mozilla does not host these old versions on their main website ( mozilla.org ). They use a dedicated archive. Here is the safe method to download. Mozilla officially maintains an FTP server at archive.mozilla.org . This is the safest source (No viruses, no fake installers).

Disclaimer: Mozilla, Firefox, and the Firefox logo are trademarks of the Mozilla Foundation. This article is for educational and archival purposes only.

The ESR (Extended Support Release) is designed for organizations. While standard Firefox 52 received security updates only until September 2017, . For Windows XP users, Mozilla extended this specifically to 52.9.0 ESR .

Posted by Legacy Software Team | Updated: October 2024