How can I find out which Postfix version I'm running?

This short guide shows you how to find the version number of your Postfix email server. Unlike many other applications, Postfix has no -v or --versions switch. But you can get the version information easily by using the postconf command as shown below:

Run this command as root user to get the Postfix version:

postconf mail_version

an alternative command is:

postconf -d | grep mail_version

The above command is compatible with all Linux operating systems incl. CentOS, Debian, Fedora, and Ubuntu.