Assuming, for the sake of the user, that RedCAD 2.5 (version 11) is a real software and they need help finding it. The first step would be to advise visiting the official website for downloads. If the official site is unavailable, they might need to check the developer's contact information or community forums. However, I must emphasize that sharing or providing direct download links to unlicensed software is against the policy and legal guidelines.