TLS 1_2 support with ssmtp

Hello, send an email via ssmtp in tls, I glimpse myself that ssmtp only supported the tls 1.0, is it possible to activate the tls 1.2 support (via lgnutls-openssl (libgnutls-openssl27)).

For information: on Arch Linux, ssmtp sends well tls 1.2 (but via libssl (openssl)).

ssmtp configuration :
<email address hidden>
mailhub=smtp.gmail.com:587
hostname=pc
UseTLS=YES
UseSTARTTLS=YES
AuthUser=gagzou
AuthPass=xxxxxxxx

I give you SMTP header :

With Ubuntu 14.04 LTS (vm minimal installation) :
Received: from pc (LFbn-1-3117-20.w90-79.abo.wanadoo.fr.)
        by smtp.gmail.com with ESMTPSA id w129sm4589737wmd.9.2016.09.23.12.45.18
        for <email address hidden>
        (version=TLS1 cipher=AES128-SHA bits=128/128);
        Fri, 23 Sep 2016 12:45:19 -0700 (PDT)

With Arch :
Received: from pc (LFbn-1-3117-20.w90-79.abo.wanadoo.fr.)
        by smtp.gmail.com with ESMTPSA id r8sm8470924wjs.22.2016.09.23.11.40.31
        for <email address hidden>
        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
        Fri, 23 Sep 2016 11:40:31 -0700 (PDT)

Thank you.