* **OpenTSDB**: Support nested template variables in tag_values function, closes [4398](https://github.com/grafana/grafana/issues/4398)
* **Datasource**: Pending data source requests are cancelled before new ones are issues (Graphite & Prometheus), closes [5321](https://github.com/grafana/grafana/issues/5321)
## Breaking changes
### Breaking changes
* **Logging** : Changed default logging output format (now structured into message, and key value pairs, with logger key acting as component). You can also no change in config to json log ouput.
* **Graphite** : The Graph panel no longer have a Graphite PNG option. closes #[5367](https://github.com/grafana/grafana/issues/5367)
* **Panel**: Fixed blank dashboard issue when switching to other dashboard while in fullscreen edit mode, fixes [#5163](https://github.com/grafana/grafana/pull/5163)
* **Templating**: Fixed issue with nested multi select variables and cascading and updating child variable selection state, fixes [#4861](https://github.com/grafana/grafana/pull/4861)