Bigip mgmt port using tls 1.0 for smtp connection

Hi,

We running 15.1.5.1

We did the smtp config from GUI and used the test button - we usue mgmt port for this config - it keeps using tls 1.0 but our mimecast server supports tls 1.2, how can i make the mgmt port use tls 1.0 for this connection?

The client hello shows it using tls 1.0.. i cant find any option to change this!