(765 ILCS 835/11) (from Ch. 21, par. 21.4)
    Sec. 11. All persons so named in such petition, except the petitioner, shall be made parties defendant by name, and if the name or names of any owner or claimant are alleged in the petition to be unknown, such persons shall be made parties defendant under the name and style of "Unknown Owners". All parties defendant shall be notified of the pendency of the proceeding in the same manner as is now or may hereafter be required in other civil cases.
(Source: Laws 1961, p. 2908.)