andare in impostazioni e digitare sulla barra about:config

There are TLS settings prefs on the about:config page that specify the minimum and maximum TLS version.

• security.tls.version.min = 1
• security.tls.version.max = 3

1 means TLS 1.0 2 means TLS 1.1 3 means TLS 1.2 (default) 4 means TLS 1.3;

• http://kb.mozillazine.org/security.tls.version.*