This is an announcement of an IETF-wide Call for Comment on draft-iab-iotsi-workshop-02. The document is being considered for publication as an Informational RFC within the IAB stream, and is available for inspection at: https://datatracker.ietf.org/doc/draft-iab-iotsi-workshop/ The Call for Comment will last until 2018-08-13. Please send comments to architecture-discuss@ietf.org and iab@iab.org. Abstract This document provides a summary of the 'Workshop on Internet of Things (IoT) Semantic Interoperability (IOTSI)', which took place in Santa Clara, California, on March 17-18, 2016. The main goal of the workshop was to foster a discussion on the different approaches used by companies and Standards Developing Organizations (SDOs) to accomplish interoperability at the application layer. This report summarizes the discussions, and lists recommendations to the standards community. The views and positions in this report are those of the workshop participants and do not necessarily reflect those of the authors and the Internet Architecture Board (IAB), which organized the workshop.