Change Facebook to Old Design (before Sep 2020) by changing your browser's configuration to one not supported by the new Facebook
Turn back to the old version of Facebook. Facebook doesn't allow to do it through settings?
Use this small extension with easy design to revert to Facebook old layout. All you need - just choose what version you like!
Extension saves your setting automatically and you don't need to change it every time you open browser.
Copyright note: Facebook™ is a registered trademark of Facebook Inc. This extension is neither endorsed by or affiliated with Facebook.