(The last version before the 52 ESR transition) Why use Firefox 52 ESR?
Using versions 12–51 or 52 ESR in 2026 poses . These browsers lack modern protections against web vulnerabilities. It is strongly recommended to use the Current Firefox Release for daily browsing. Download Firefox 12-51 52 Esr
https://archive.mozilla.org/pub/firefox/releases/12.0/win32/en-US/Firefox%20Setup%2012.0.exe (The last version before the 52 ESR transition)
: Firefox 12 was the final version to support Windows 2000 and the original/SP1 versions of Windows XP. Firefox 52 ESR was the absolute final release compatible with Windows XP and Windows Vista. Flash and NPAPI Plugins Download Firefox 12-51 52 Esr