Unable do connect to Elastic 7

Just upgraded Elastic to version 7 and grafana stopped working.
Data sources show
“No date field named @timestamp found”

Grafana version 6.1.3.
all DS working fine with EL 6.7

There’s an open feature request for support Elasticsearch 7, see and upvote if interested https://github.com/grafana/grafana/issues/15622.