Grafana 4.0 Stable Release

Grafana 4.0 marks a significant upgrade with the introduction of alerting, transforming it from a visualization tool into a critical monitoring resource. This new feature allows users to configure alert rules using existing graph panels, with notifications sent out when conditions are met, though currently limited to certain data source plugins like Graphite, Prometheus, InfluxDB, and OpenTSDB. The release also includes an alert list panel for tracking rule state changes, ad-hoc filter variables for creating dynamic key/value filters, and numerous UX improvements such as TV and kiosk modes for streamlined displays. Annotations are now recorded in an internal database, with future plans for user-added graph comments, while enhancements in the dashboard building experience include more intuitive drag-and-drop features and keyboard shortcuts. Notably, there are no breaking changes, ensuring compatibility with existing dashboards, while users are encouraged to update plugins for optimal functionality.