Grafana7.1,timefield can't setting type in Elasticsearch

hi,in grafana6, I can setting date type of timefield ,such as YYYY:MM:DD or YYYY:MM:DD hh:mm:s
but I can’t find this feature in grafana 7.1,please tell me how to do

Use the override on the top right

i try to use unit,but it can’t work,please guide me how to do,thx~