PATCH success "ok" field has wrong JSON value

Both "ok" leafs in the PATCH output are of type empty.
https://tools.ietf.org/html/draft-ietf-netconf-yang-patch-08#section-3

The value should be written either as [null] or as {} (depending on Restconf draft version). But currently the value is written as null.

$ curl -u'admin:admin' -X PATCH -H "Content-Type:application/yang.patch+json" -d '{"ietf-restconf:yang-patch":{"patch-id":"0","edit":[{"edit-id":"0","operation":"replace","target":"/car:car-entry[car:id='"'"'0'"'"']","value":{"car:car-entry":[

]}}]}' 127.0.0.1:8181/restconf/config/car:cars ;echo

{"ietf-yang-patch:yang-patch-status":

}