Hi TC, Is there a plan to release an Interoperability Document for STIX/TAXII 2.1 CD01? Based on the sponsorship approach we started with STIX/TAXII 2.1 CSD01, we should have the requirements for generating an Interoperability document by April 2019 if not sooner (give or take time for finalizing editorial tweaks). Releasing an Interoperability Document for CSD01 seems like a natural next step and would encourage 2.1 adoption prior to the approval of a CS by providing official TC documentation to those in the global community willing to implement/integrate STIX/TAXII 2.1 during the CSD phases. Marlon Taylor Program Management Branch National Cybersecurity & Communications Integration Center (NCCIC) U.S. Department of Homeland Security