All application licensing schemes employ a limit on the number of mailboxes that are protected by the application.
Licensing a Security Server:
Trial license. A license for trial use of the application. It is granted for a specific period that is assigned by Kaspersky. When the trial license expires, all application features become disabled. You can activate the application using a key or activation code.
Commercial. A license for commercial use of the application. It is granted for a specific period that is assigned by Kaspersky when the license is purchased. When the commercial license expires, the application continues to work in limited functionality mode. The user is no longer able to update the application databases, receive new application versions, or contact Technical Support. You can activate the application using a key or activation code.
Commercial (subscription). A license for commercial use of the application distributed through vendors based on a subscription. It is granted for a specific period that is assigned by the vendor based on a subscription. According to the license restriction, you can use the application during the period for which you purchased a subscription from the vendor. You can activate the application with an activation code, but you cannot activate the application with a key.