Once you have purchased a valid MailMan license, you will be given access to the licensed MailMan distribution. The licensed distribution is identical to the demo distribution except that the script file in the demo distribution expires after 30 days, where the licensed script file will never expire.

To install the licensed script file, just unpack your licensed distribution and replace your demo copy of the "mailman.cgi" file with the one from your licensed distribution. Be sure to make any configuration changes that you need at the top of the script file. You do not need to replace any of the template files because they are exactly the same in both distributions, the only difference is the script file itself.