625 ILCS 5/3-829
In any action to foreclose the lien imposed by Section 3-828 service of process on all known owners and parties in interest shall be made in the manner now prescribed by law, and, as to all unknown owners and parties in interest, notice of the pendency of such action shall be given by publication in some newspaper of general circulation published in the county where the suit is pending, or if there is no such newspaper, then in a newspaper of general circulation published in an adjoining county in this State and having a general circulation in the county in which such suit is pending. Such notice shall contain the title of the court; the title of the case, showing the names of all known owners and parties in interest; a statement that publication is being made as to unknown owners and parties in interest; and the date on or after which default may be entered against the defendants.
625 ILCS 5/3-829