In PNC Bank v. Unknown Heirs, 2007 PA Super 212, 929 A.2d 219 (Pa. Super. 2007), the Superior Court addressed whether an order permitting alternative service failed to satisfy the requirements of due process. In that case, a mortgagee sought foreclosure against a deceased mortgagor, his unknown heirs, and other parties with potential interests in the property. The mortgagee moved for alternative service, averring a diligent yet unsuccessful search for information regarding the mortgagor's successors in interest. The trial court granted the mortgagee's motion and permitted alternative service by certified and first-class mail to the mortgaged premises, publication, and posting at the mortgaged premises. The mortgagee made service in accordance with the trial court's order and subsequently obtained a default judgment of foreclosure on the deceased mortgagor, his unknown heirs and assigns, and other parties with potential interests in the property. Some months later, a successor in interest to the deceased mortgagor petitioned the trial court to open the default judgment. On appeal after the petition was denied, and the Superior Court reversed based on the inadequacy of the alternative service. The Court concluded the trial court authorized inadequate methods of alternative service because, despite the mortgagee's affidavit of good-faith investigation, the record indicated a known, potential heir. Accordingly, the methods of alternative service did not satisfy the requirements of due process because, clearly, the method of alternative service most reasonably calculated to notify a potential party would include personal service upon a known, potential heir.