We never recommend running an outdated version of Firefox. The developers are always working to improve Firefox. This includes fixing any privacy or security issues that arise. Running an old version may leave you vulnerable to those issues. You can prevent updates by using either [[Customizing Firefox Using Group Policy|group policy]] or [[Customizing Firefox Using policies.json|a policies.json file]], but this is recommended for business environments <u>'''only'''</u>. If you still have your heart set on using an old version of Firefox, you can read the [[Install an older version of Firefox]] documentation for more information on installing an older version. But again, I would never recommend that. Fortunately, Firefox is a highly customizable software, so it's likely that you can customize it to suit your needs. Truth be told, Firefox hasn't really changed a whole lot (visually) for a quite a few versions now. Is there a particular feature in the new version that you don't like? Odds are, you will be able to disable it or modify it.