When installing OpenNMS Helm we rely on Grafana. In the documentation we tell vary vague a Grafana between 4.4.1 < 6 is required. The latest version of Grafana today is 6.5.3 and it seems like our plugin can only be used up to the latest 6.4.5 version and is not compatible with the latest stable 6.5.3 version. We should be more specific with the compatible version number. The latest dependency in Helm itself is set to "@grafana/data": "^6.4.3",.