Most titles end publication at one time or another, with or without completing the series. The Acquisitions team will pass on any such information to the A/V cataloger, but sometimes there is no formal notification from the publisher so it is necessary to check each latest volume itself via the book jacket (if present) and/or the forewords or introduction in the volume.
*However if there is a gap in the number of volumes that we have (v. <1-3, 5> change it to the known total of published volumes (5 volumes). People will see in OPAC which volumes we do have.