>> Can someone tell me how I can use this software and what I cannot do? > > I believe that this is what you're looking for: > > https://github.com/rspamd/rspamd/blob/master/LICENSE.md These might also be of interest: https://rspamd.com/doc/other/usage_policy.html https://rspamd.com/commercial.html https://shop.rspamd.com Best regards, Gerald