Using Data Replication Data Adaptors, I updated the resource schema and added updated data (see The schema for my datasource has changed how do I update my Data Replication resource? ). I already have Data Replication clients who have registered for this resource. Do they need to do anything to handle the new schema?

An existing implementation of the Data Replication client will not need to do anything specific with its current registration with an update resource. The Data Replication client will automatically detect the updated resource schema and sync the full schema and data on the next sync request. 

Your app or application will need to adjust its local query based upon the new schema of course.