I installed SSL Let's Encrypt certificate on a small VPS and domains work fine with independent SSL certificate and Apache. Unfortunately, the emails for each domain does not work with SSL, due to the certificate mismatch which is a problem of Postfix, this is the VPS software:
Postfix version 3.4 works with SNI solving the issue with virtual domains and SSL email using SNI.
Software Versions
Operating system CentOS Linux 7.8.2003
Perl version 5.016003
BIND version 9.11
Postfix version 2.10.1
Apache version 2.4.6
PHP versions 5.4.16, 5.6.25, 7.2.24
Webalizer version 2.23-08
Logrotate version 3.8.6
MySQL version 5.5.65
ProFTPD version 1.35
SpamAssassin version 3.4.0
ClamAV version 0.99.2
Webmin version 1.942
Virtualmin version 6.09
Usermin version 1.791
Question: Can I safely upgrade Postfix version 2.10.1 to Postfix 3.4 on CentOS 7.8.2003?
Postfix 3.4 is not in base repository, only verrsion 2:2.10.1-9.el7 is.
Thanks and regards.
joejac