(Each of the tar, RedHat and SuSE versions is a compressed tar file. Download it, unpack it (with "tar xzvf MailScanner*tar.gz") and run the "install.sh" script in it.)
Note: The FreeBSD version is a BSD "port". Please read the instructions.
The Change Log lists all the updates, additions, fixes and other changes that have happened to MailScanner. Check here to see whether you might want to upgrade to the latest version, by reading the lists of new features and changes to find if any of them affect you.