Whisper is a free chat application developed by IBR TU Braunschweig for Android users. This app is specifically designed to work with the IBR-DTN services, which must be installed beforehand. Without the necessary permissions, the app will not function properly.

With Whisper, users can easily connect with their contacts and send messages through the IBR-DTN network. Additionally, if the Talkie app is installed, users can also send voice messages to their contacts. The interface of the app is simple and easy to navigate, making it a convenient option for sending messages through the IBR-DTN network.

Overall, Whisper is a great chat application for those who use the IBR-DTN network. While it does require some additional setup, the app is easy to use and offers a reliable messaging experience.