Firefox 52 ESR is one of the most famous legacy browsers in internet history.
: It supports older "XUL" based extensions that were disabled in Firefox 57 (Quantum). Important Security Warning Download Firefox 12-51 52 Esr
Microsoft's SmartScreen often blocks old MSI/EXE installers. You will need to click "More info" and then "Run anyway." Alternatively, use a Windows 7 virtual machine. Firefox 52 ESR is one of the most