I did a security scan on my system (i-mscp 1.2.15) and I think the following advisories are important:
1. Missing httpOnly Cookie Attribute
Set session.cookie_httponly = true in all php.ini files.
see: https://www.owasp.org/index.php/HttpOnly
2. SSL Weak Ciphers in POP3S, IMAPS, SMTPS, POP3-SSL, IMAP-SSL, SMTP-SSL
Add default secure ciphers.