While you have the option to low security in order to support legacy devices and browsers, it is not recommended to lower the ciphers and TLS version as this leaves you can leave you extremely vulnerable to security flaws. TLSv1.1 is recommended minimum.
You can enable support for older devices & browsers by updating ssl_prefer_server_ciphers, ssl_protocols and ssl_ciphers. ssl_prefer_server_ciphers tells the web server to prefer server ciphers instead of client ciphers. ssl_protocols define the TLS versions the web server should allow and ssl_ciphers defines the supported ciphers.
When you first setup a site through Laravel Forge and enable the Let’s Encrypt certificate the default protocols and ciphers are the following.
ssl_protocols TLSv1.2;
ssl_prefer_server_ciphers on;
ssl_ciphers ECDHE-RSA-AES256-GCM-SHA512:DHE-RSA-AES256-GCM-SHA512:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384;
Using this configuration limits connections to TLS v1.2 and newer devices and browsers. It is generally not recommended to support less than TLS v1.1 due to downgrade attacks and other vulnerabilities in TLS v1.0 and below.
If you wish to support older devices (but weaken security in the process) then the following configuration is recommended.
ssl_protocols TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;
ssl_ciphers "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH:ECDHE-RSA-AES128-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA128:DHE-RSA-AES128-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES128-GCM-SHA128:ECDHE-RSA-AES128-SHA384:ECDHE-RSA-AES128-SHA128:ECDHE-RSA-AES128-SHA:ECDHE-RSA-AES128-SHA:DHE-RSA-AES128-SHA128:DHE-RSA-AES128-SHA128:DHE-RSA-AES128-SHA:DHE-RSA-AES128-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA384:AES128-GCM-SHA128:AES128-SHA128:AES128-SHA128:AES128-SHA:AES128-SHA:DES-CBC3-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4";
You can optionally change ssl_protocols to use TLS v1.0 instead, however this is not recommended.
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
A good place to look for configurations for older devices and recommended configurations (for many different web servers) is Cipherli.st.