SSL: ssl_conf_command directive. With the ssl_conf_command directive it is now possible to set arbitrary OpenSSL configuration parameters as long as nginx is compiled with OpenSSL 1.0.2 or later. Full list of available configuration commands can be found in the SSL_CONF_cmd manual page (https://www.openssl.org/docs/man1.1.1/man3/SSL_CONF_cmd.html). In particular, this allows configuring PrioritizeChaCha option (ticket #1445): ssl_conf_command Options PrioritizeChaCha; It can be also used to configure TLSv1.3 ciphers in OpenSSL, which fails to configure them via the SSL_CTX_set_cipher_list() interface (ticket #1529): ssl_conf_command Ciphersuites TLS_CHACHA20_POLY1305_SHA256; Configuration commands are applied after nginx own configuration for SSL, so they can be used to override anything set by nginx. Note though that configuring OpenSSL directly with ssl_conf_command might result in a behaviour nginx does not expect, and should be done with care.