(a)        Complaints or orders issued by a public officer pursuant to an ordinance adopted under this Article shall be served upon persons either personally or by certified mail. When service is made by certified mail, a copy of the complaint or order may also be sent by regular mail. Service shall be deemed sufficient if the certified mail is unclaimed or refused but the regular mail is not returned by the post office within 10 days after the mailing. If regular mail is used, a notice of the pending proceedings shall be posted in a conspicuous place on the premises affected.

(b)        If the identities of any owners or the whereabouts of persons are unknown and cannot be ascertained by the public officer in the exercise of reasonable diligence, or, if the owners are known but have refused to accept service by certified mail, and the public officer makes an affidavit to that effect, then the serving of the complaint or order upon the owners or other persons may be made by publication in a newspaper having general circulation in the jurisdiction at least once no later than the time at which personal service would be required under the provisions of this Article. When service is made by publication, a notice of the pending proceedings shall be posted in a conspicuous place on the premises thereby affected. ?(2019-111, s. 2.4; 2020-3, s. 4.33(a); 2020-25, s. 51(a), (b), (d).)