DiffDaff is freeware so you may use it for any purpose for free. You will find all the details in the “End User License Agreement” that is part of the setup procedure for DiffDaff. You must agree to that license before using it!
In the main program dialog a page from the web will be loaded on every startup. This page informs you about available updates and also contains some advertising. This advertising will help us to finance the further development of the software.