From the ARRL ARES e-Letter from 20 March 2019:

FEMA released IS-200.c this past week. IS-200.c, Basic Incident Command System for Initial Response, ICS 200, is designed to enable personnel to operate efficiently during an incident or event within the Incident Command System (ICS). This course focuses on the management of single resources. IS-0200.c provides training on and resources for personnel who are likely to assume a supervisory position within the ICS.

If you have successfully completed a previous version of this course there is no FEMA requirement to take the revised version of the course. However, because this course contains new information based on the revised NIMS, October 2017, you may find it informative to review the new version. The new material is available through the EMI website.