Docs: What's new 6.4 draft (#19144)

* What's new 6.4 draft

* data model notes

* minor progress

* Only include top highlights list

docs/sources/features/panels/graph.md

@@ -210,6 +210,9 @@ available suggestions:
 
 #### Built-in variables
 
+> These variables changed in 6.4 so if you have an older version of Grafana please use the version picker to select
+docs for an older version of Grafana.
+
 ``__url_time_range`` - current dashboard's time range (i.e. ``?from=now-6h&to=now``)
 ``__from`` - current dashboard's time range from value
 ``__to`` - current dashboard's time range to value
@@ -240,7 +243,6 @@ Value specific variables are available under ``__value`` namespace:
 ``__value.calc`` - calculation name if the value is result of calculation
 
 
-
 #### Template variables
 
 When linking to another dashboard that uses template variables, you can use ``var-myvar=${myvar}`` syntax (where ``myvar`` is a name of template variable)

docs/sources/guides/whats-new-in-v6-4.md

++++
+title = "What's New in Grafana v6.4"
+description = "Feature & improvement highlights for Grafana v6.4"
+keywords = ["grafana", "new", "documentation", "6.4"]
+type = "docs"
+[menu.docs]
+name = "Version 6.4"
+identifier = "v6.4"
+parent = "whatsnew"
+weight = -15
++++
+
+# What's New in Grafana v6.4
+
+For all details please read the full [CHANGELOG.md](https://github.com/grafana/grafana/blob/master/CHANGELOG.md)
+
+## Highlights
+
+Grafana 6.4 comes with a lot of new features and enhancements backed with tons of work around the data models and query
+execution that is going to enable powerful future capabilities. Some of those new capabilities can already be seen in
+this release, like sharing query results between panels.
+
+- [**Explore:** Go back to dashboard (with query changes)]({{< relref "#go-back-to-dashboard-from-explore" >}})
+- [**Explore:** Live tailing improvements]({{< relref "#live-tailing-improvements" >}})
+- [**Loki:** Show logs as annotations in dashboard graphs]({{< relref "#loki-annotations" >}})
+- [**Loki:** Use Loki in dashboard panels]({{< relref "#loki-in-dashbaords" >}})
+- [**Panels:** New logs panel]({{< relref "#new-logs-panel" >}})
+- [**Panels:** Data links improvements]({{< relref "#data-links-improvements" >}})
+- [**Dashboard:** Share query results between panels]({{< relref "#share-query-results" >}})
+- [**Plugins:** Alpha version of grafana-toolkit]({{< relref "#alpha-version-of-grafana-toolkit" >}})
+- [**ImageRendering:** PhantomJS deprecation]({{< relref "#phantomjs-deprecation" >}})
+- [**Docker:** Alpine based docker image]({{< relref "#alpine-based-docker-image" >}})
+- [**LDAP Debug View**: Reporting]({{< relref "#ldap-debug-view" >}})
+- [**Enterprise**: Reporting]({{< relref "#reporting" >}})
+- [**Enterprise**: GitLab OAuth Team Sync support]({{< relref "#gitlab-oauth-team-sync-support" >}})
+- [**Enterprise**: Teams & LDAP Improvements]({{< relref "#ldap-teams" >}})
+
+
+More details on the above coming soon!