***Slack**: Removed _Mention_ setting and instead introduce _Mention Users_, _Mention Groups_, and _Mention Channel_. The first two settings require user and group IDs, respectively. This change was necessary because the way of mentioning via the Slack API [changed](https://api.slack.com/changelog/2017-09-the-one-about-usernames) and mentions in Slack notifications no longer worked.
You can test your plugin with the `master` branch version of Grafana.
### Features / Enhancements
***API**: Include IP address when logging request error. [#21596](https://github.com/grafana/grafana/pull/21596), [@thedeveloperr](https://github.com/thedeveloperr)
***Alerting**: Support passing tags to Pagerduty and allow notification on specific event categories . [#21335](https://github.com/grafana/grafana/pull/21335), [@johntdyer](https://github.com/johntdyer)
***Chore**: Remove angular dependency from backendSrv. [#20999](https://github.com/grafana/grafana/pull/20999), [@kaydelaney](https://github.com/kaydelaney)
***CloudWatch**: Surround dimension names with double quotes. [#22222](https://github.com/grafana/grafana/pull/22222), [@jeet-parekh](https://github.com/jeet-parekh)
***CloudWatch**: updated metrics and dimensions for Athena, DocDB, and Route53Resolver. [#22604](https://github.com/grafana/grafana/pull/22604), [@jeet-parekh](https://github.com/jeet-parekh)
***Dashboard**: Adds support for a global minimum dashboard refresh interval. [#19416](https://github.com/grafana/grafana/pull/19416), [@lfroment0](https://github.com/lfroment0)
***DatasourceEditor**: Add UI to edit custom HTTP headers. [#17846](https://github.com/grafana/grafana/pull/17846), [@adrien-f](https://github.com/adrien-f)
***Elastic**: To get fields, start with today's index and go backwards. [#22318](https://github.com/grafana/grafana/pull/22318), [@ChadiEM](https://github.com/ChadiEM)
***Explore**: Rich history. [#22570](https://github.com/grafana/grafana/pull/22570), [@ivanahuckova](https://github.com/ivanahuckova)
***Graph**: canvas's Stroke is executed after loop. [#22610](https://github.com/grafana/grafana/pull/22610), [@merturl](https://github.com/merturl)
***Image Rendering**: Store render key in remote cache to enable renderer to callback to public/load balancer URL when running in HA mode. [#22031](https://github.com/grafana/grafana/pull/22031), [@marefr](https://github.com/marefr)
***LDAP**: Add fallback to search_base_dns if group_search_base_dns is undefined.. [#21263](https://github.com/grafana/grafana/pull/21263), [@bb-Ricardo](https://github.com/bb-Ricardo)
***OAuth**: Implement Azure AD provide. [#20030](https://github.com/grafana/grafana/pull/20030), [@twendt](https://github.com/twendt)
***Prometheus**: Implement region annotation. [#22225](https://github.com/grafana/grafana/pull/22225), [@secustor](https://github.com/secustor)
***Prometheus**: make $__range more precise. [#21722](https://github.com/grafana/grafana/pull/21722), [@bmerry](https://github.com/bmerry)
***Promethus**: Do not show rate hint when increase function is used in query. [#21955](https://github.com/grafana/grafana/pull/21955), [@fredwangwang](https://github.com/fredwangwang)
***Templating**: Add new global built-in variables. [#21790](https://github.com/grafana/grafana/pull/21790), [@dcastanier](https://github.com/dcastanier)
***Reporting**: add concurrent render limit to settings (Enterprise)
***Reporting**: Add rendering timeout in settings (Enterprise)
***Alerting**: Don't include image_url field with Slack message if empty. [#22372](https://github.com/grafana/grafana/pull/22372), [@aknuds1](https://github.com/aknuds1)
***Alerting**: Fixed bad background color for default notifications in alert tab . [#22660](https://github.com/grafana/grafana/pull/22660), [@krvajal](https://github.com/krvajal)
***Annotations**: In table panel when setting transform to annotation, they will now show up right away without a manual refresh. [#22323](https://github.com/grafana/grafana/pull/22323), [@krvajal](https://github.com/krvajal)
***Azure Monitor**: Fix app insights source to allow for new __timeFrom and __timeTo. [#21879](https://github.com/grafana/grafana/pull/21879), [@ChadNedzlek](https://github.com/ChadNedzlek)
***BackendSrv**: Fixes POST body for form data. [#21714](https://github.com/grafana/grafana/pull/21714), [@hugohaggmark](https://github.com/hugohaggmark)
***CloudWatch**: Expand alias variables when query yields no result. [#22695](https://github.com/grafana/grafana/pull/22695), [@sunker](https://github.com/sunker)
***Dashboard**: Fix bug with NaN in alerting. [#22053](https://github.com/grafana/grafana/pull/22053), [@a-melnyk](https://github.com/a-melnyk)
***Explore**: Fix display of multiline logs in log panel and explore. [#22057](https://github.com/grafana/grafana/pull/22057), [@thomasdraebing](https://github.com/thomasdraebing)
***Heatmap**: Legend color range is incorrect when using custom min/max. [#21748](https://github.com/grafana/grafana/pull/21748), [@sv5d](https://github.com/sv5d)
***Security**: Fixed XSS issue in dashboard history diff . [#22680](https://github.com/grafana/grafana/pull/22680), [@torkelo](https://github.com/torkelo)
***StatPanel**: Fixes base color is being used for null values .
