Prior to ES 6 docvalue_fields on dates returned ms, now it returns a formatted date. Would be nice if that formatting could be specified, including allowing epoch_millis.

https://www.elastic.co/guide/en/elasticsearch/reference/current/date.html
Says that "The first format will be used to convert the milliseconds-since-the-epoch value back into a string.", so maybe this is a bug and not a feature request, but it doesn't seem to work.