Today we disabled the deprecated protocols TLS 1.0 and 1.1.
Unauthenticated mail via SMTP on port 25/tcp does still accept >= TLS 1.0 . It is better to accept a weak encryption than none at all.
How to re-enable weak protocols?
nano data/conf/postfix/extra.cf
submission_smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3 smtps_smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3
nano data/conf/dovecot/extra.conf
ssl_min_protocol = TLSv1
Restart the affected services:
docker-compose restart postfix-mailcow dovecot-mailcow
Hint: You can enable TLS 1.2 in Windows 7.