Very little in the way of official documentation on upgrading MailScanner on RPM based distributions so here is a 30 second tutorial.

1.    Grab a copy of the package you wish to upgrade to, from mailscanner.info
2.    Stop any MailScanner processes
3.    Extract the file with ‘tar –zxvf MailScanner-X.X.X.rpm.tar.gz’ and enter the directory
4.    Start the upgrade by simply running the ‘install’ script within – this will take 10 or so minutes
5.    Change dir to /etc/MailScanner
6.    Run ‘upgrade_MailScanner_conf MailScanner.conf MailScanner.conf.rpmnew > MailScanner.new’
7.    Optionally view what has been changed with ‘diff -w MailScanner.conf.rpmnew MailScanner.new’
8.    mv MailScanner.conf MailScanner.old
9.    mv MailScanner.new MailScanner.conf
10.  Restart MailScanner
Simple.