We would like to thank all participants and guests who attended OPIC2017, 18-21 April 2017.We hope that your time at the congress was stimulating and rewarding. Therefore, we would like to send all participants and guests the request for the brief online survey about OPIC2017 later. Your feedback is extremely valuable to refine OPIC2018 (23-27 April) in the coming year. The survey will be available online through Friday 12 May, 2017.