If after an order of publication has been executed, the defendants or unknown parties against whom it is entered shall not appear on or before the date specified in such order, the case may be tried or heard as to them. When the provisions of § 8.01-317 have been complied with, no other publication or notice shall thereafter be required in any proceeding in court, or before a commissioner, or for the purpose of taking depositions, unless specifically ordered by the court as to such defendants or unknown parties.