Versola is distributed under the Versola Community License v1.0. It is source-available, not open source. In short, it is free for internal authentication of employees in small organisations, and any organisation can evaluate it. Other uses, such as authenticating customers or offering Versola as a hosted service, need a commercial licence.
A commercial licence is available on request. The contact details are in the Contact section of the licence.
This page is a summary, not legal advice. The licence text governs.