After many iterations and plenty of user interviews we got a better understanding about what customers want. Of course there where many hypothesis and questions we had. Some of them seemed to be right, some of them seemed to be wrong. For example that many people are planning a vacation with friends in WhatsApp (or Facebook) Groups seemed to be right. another one which seemed to be right was that the planing process always is a pain because of the lack of structure. Out of that assumptions and our plan we finished our MVP and tested several features with a small group of 10 people who gave as valuable feedback one our idea!