This postmortem report will provide all readers with important information about the Open Science workshop which took place in Vienna, Austria on the 20th of September 2017. The workshop was organised by the Open Innovation in Science Research and Competence Center, Open Access Austria, Austrian Transition to Open Access and Open Knowledge Austria. All authors of this document participated at this Open Science workshop and contributed to the report in a collaborative writing effort. In this report, readers will find an overview about the Open Science Workshop structure, presented content of the workshop, all slides pictures, social media interactions and everything we have learned from organising this highly important workshop on Open Science.