For developers and testers needing every specific iteration, Mozilla maintains a public Directory of All Releases . You can browse this index to find folders labeled with "esr," such as 128.0esr/ or 102.0esr/ . Firefox ESR Release History Overview
Since its introduction with Firefox 10, the ESR branch has followed a predictable cycle where new major versions overlap with the previous ones to allow for organizational testing. Directory Listing: /pub/firefox/releases/ - mozilla.org firefox esr all versions download
The last version to support Windows XP and Windows Vista. For developers and testers needing every specific iteration,
Firefox Extended Support Release (ESR) is a specialized version of the Firefox browser designed for schools, businesses, and organizations that need a stable platform with long-term security support. Unlike the standard "Rapid Release" Firefox, which updates features every four weeks, ESR versions focus on security and stability for over a year. Where to Download All Versions of Firefox ESR Directory Listing: /pub/firefox/releases/ - mozilla
Older versions are often sought for compatibility with specific operating systems:
Whether you need the newest security patch or an older version for legacy system compatibility, here is how to find the official downloads:
The final supported version for Windows 7, Windows 8, Windows 8.1, and macOS 10.12 through 10.14.