Mozilla no longer lists very old ESR builds on the main site. Use Mozilla FTP archive or reputable archives that host old releases. Examples (use at your own risk):
Do you need to run specific like Java or Silverlight?
Select your preferred language code folder (e.g., en-US for English - United States). Download the .exe , .dmg , or .tar.bz2 installer file. Technical Specifications & System Compatibility firefox version 52.9. 0 esr download
Beyond OS compatibility, 52.9.0 ESR was significant for what it preserved—and what it transitioned away from: NPAPI Plugins:
It was one of the first ESR builds to offer experimental support for TLS 1.3, the encryption standard for HTTPS. Mozilla no longer lists very old ESR builds on the main site
Furthermore, 52.9.0 holds a critical, if shrinking, role in the world of legacy technology. In an age where the web is increasingly hostile to older hardware, this browser is a lifeline. It supports Windows XP and Vista—operating systems that modern browsers have long abandoned. In schools with aging computer labs, in factories running industrial machinery on Windows XP kiosks, and in the laptops of users who cannot afford modern hardware, 52.9.0 ESR serves as the last bridge to the modern web. It provides a secure (albeit outdated) tunnel to the internet where none would otherwise exist.
This version is historically significant because it was the before Mozilla pushed its sweeping "WebExtensions-only" policy (Firefox 57+, codenamed "Quantum"). It was also the final version of Firefox to support older operating systems , including: Select your preferred language code folder (e
Mozilla officially dropped support for Windows XP and Windows Vista after this release. If you run these operating systems on vintage gaming rigs, industrial machines, or medical equipment, 52.9.0 ESR is the most modern and secure version of Firefox you can run. Preservation of NPAPI Plugin Support
If you need help setting up like Java or configuring the browser for a particular vintage website , let me know how you plan to use it so I can provide tailored instructions. Share public link
Firefox version (Extended Support Release), released in June 2018, is a legacy browser primarily used today to maintain compatibility with older hardware and software . It is the final version of Firefox that supports Windows XP and Windows Vista . Key Features and Use Cases
: It is the last official release for Windows XP (SP2 or higher) and Windows Vista .