Due date of the next task in line (displayed in related projects database)

"Next task is due: " + 
  filter(
    prop("Tasks"),
    current.prop("Status").contains("Not started") 
    || /* Comment: Using "||" is equvalent to using "or"*/
    current.prop("Status").contains("In progress")
  )
  .map(current.prop("Date"))
  .sort()
  .first()