RFS (Retro FPS Studio) works with a license system. You get an e-mail with your key, and entering both into RFS, you can then use it. This system is designed to be lightweight, and to not bother you after once activated: there is no always online requirement, just a one time check during this activation. There is also no intrusive computer scanning to detect piracy tools, or something like that.
Please contact us via e-mail: el AT horse64 DOT org
(Insert the @ and the . characters into above e-mail
address. It needs to be written like that due to spam bots.)
No, RFS works offline. Past the first license activation on your machine, further update checks while recommended are optional. You're free and allowed to put RFS on some low spec, portable device, and use it out on a hike in the woods if you want! (Be careful with wild animals, however.)
See section above for revoked or invalid license for contact information. We would like to help you get it resolved.
Check your e-mail inbox, you should have a copy there.