Cyren Anti-Spam Add-on is available for the SmarterMail mail server.
It can be installed on Pro and Ent versions. However the installation must have active Upgrade Protection.
The number of mailboxes must exactly match those of your SmarterMail Installation. You can not purchase less Cyren mailboxes than your SmarterMail supports.
After your purchase we may issue a pro-rata refund. This is so that we can bring into line all your Add-on and Upgrade Protection renewals to the same date.