Type: enum
Context: sighup
Restart: false
Values: [, TLSv1, TLSv1.1, TLSv1.2, TLSv1.3]
Since: 12

Sets the maximum SSL/TLS protocol version to use. Valid values are as for ssl_min_protocol_version, with addition of an empty string, which allows any protocol version. The default is to allow any version. Setting the maximum protocol version is mainly useful for testing or if some component has issues working with a newer protocol.