Rancher 2.5 introduces a new, improved monitoring integration. It is still based on Prometheus, Grafana and Alertmanager, but much more flexible regarding configuration options and customizations. It also directly ships with much improved dashboards and alerting rules. Unfortunately, due to the necessary internal changes, there is no automatic upgrade path available from the old to the new monitoring. While you can continue to use the old monitoring with 2.5, there are some manual migration steps necessary to get all the benefits from the new monitoring system and keep all the configurations and customizations from the old one.