That's why I did for the Grails 4 update I worked on ending up with this:

compile('org.grails:grails-datastore-rest-client:6.1.9.RELEASE'){
	exclude group:'org.grails', module:'grails-plugin-converters'
}

And adding tickets to replacing the client, and eventually the json converts, with json views, for the future of the project I'm working on.