When real estate is sold for taxes, the Greenville County Tax Collector shall give not less than thirty days’ notice of the sale to any mortgagee or assignee of any mortgage appearing of record within ten years of such seizure as interested in such real estate in order that such mortgagee or assignee may have opportunity to redeem such real estate as provided for the owner in Section 1.20.250 of this chapter. The notice shall be either served on the mortgagee or assignee personally or sent by registered mail to the mortgagee’s last known post office address. If the whereabouts of the mortgagee or assignee is unknown, the notice may be given by publication upon petition and order as is required for service of summons by publication in civil actions, and the costs of notice in this manner shall be paid in advance of the publication by the purchaser of the tax sale. (Prior code § 1-5-47)