Elasticsearch 5.2.0 vs 7.4 architecture

Hey folks

newbie Question:

I'm in the process of deploying a new elk stack on GKE currently using the helm templating tool
In my elk stack I've inherited there's a es-client <--- es-data . <---- es-master ) = 5.2.0 and in the new helm version 7.4.x I only see master nodes has the deployment process change ?