Mozilla Server Side TLS 5.0 – Modern SSL Generator Now Recommends TLSv1.3 Only

The use of the Old configuration with modern versions of OpenSSL may require custom builds with support for deprecated ciphers. For services with clients that support TLS 1.3 and don’t need backward compatibility, the Modern configuration provides an extremely high level of security. This configuration is compatible with a number of very old clients, and should be used only as a last resort.

Source: wiki.mozilla.org