I’m not sure. Because 2019-08-07 00:00 means the 0 hour of that day. Suppressing the time would make it look like the due date is that date, at any time, like 2019-08-07 23:59.
Kanboard paints the due date color red when it’s expired. So I think it would be confusing because it will look like the task is still on time (because we are still on 2019-08-07), but they will actually be already expired, because 00:00 it’s in the past.