Given the security risks associated with using outdated software, consider these alternatives:
If you try to run the installer on Windows 10 or 11, you may encounter an error: "This program is not compatible with the current operating system." Here is how to bypass that: download old version of mozilla firefox 3.6
Downloading an older version of Mozilla Firefox 3.6 is possible through Mozilla’s official archive , which maintains a directory of legacy releases. Given the security risks associated with using outdated