One software license is required per developer.
Run-time royalty free.

Maintenance
Purchasing any product of AfterLogic entitles you to 1 year of free maintenance of that product since the moment of purchase. The maintenance includes all major and minor updates released for that product during the year and the standard technical support.
The maintenance period can be prolonged on annual basis.

Extended Support
Entitles you to high-priority helpdesk and e-mail support and extended trouble-shooting assistance for 1 year.
If combined with "2nd year maintenance", Extended Support for 2nd year is free.

MailBee.NET Queue is free for MailBee.NET SMTP owners, please download the mailBee.NET Queue evaluation and use your exisiting MailBee.NET SMTP License Key to license MailBee.NET Queue