In Katello 4.0 the katello-agent will no longer be supported. Due to the migration to Pulp3 it will no longer work. We’re officially deprecating the agent in Katello 3.16 so there will be time for folks to adapt. We are recommending looking at the Remote Execution plugin to continue pushing updates to content hosts.
Since we’re dropping agent support in ~2 releases, there’s no plan to provide katello-agent packages for EL8.