For the desktop Firefox the TLS 1.0 and TLS 1.1 have been deprecated since Firefox 78 Release and should not be used now days.

https://blog.mozilla.org/security/2018/10/15/removing-old-versions-of-tls/ https://hacks.mozilla.org/2020/02/its-the-boot-for-tls-1-0-and-tls-1-1/

You can still enable TLS 1.0/1.1 via about:config although this is not recommended and you should only flip the pref when you need to access this device/website and reset the pref to false once you are done.

• about:config => security.tls.version.enable-deprecated => true

You can open the about:config page via the location/address bar. If you get the warning page, you can click the "Accept the Risk and Continue" button.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox