If you meet someone and nothing happens after 18 days (you or him getting sick) it means you're both safe. Therefore, any contact logs older than 18 days are automatically deleted.
If one of your peers is infected you'll find out how you're connected. This way, you can take safety measures as self-isolating or getting tested for COVID-19.
This platform is made by a group of self-isolated friends with the only reason to stop the spreading of COVID-19.