Delaware Code Title 25. Property § 5706. Manner of service

(1) Upon a natural person by affixing a copy of the notice and complaint upon a conspicuous part of the rental unit within 1 day thereafter, and by sending by either certified mail or first class mail with certificate of mailing, using United States Postal Service Form 3817 or its successor, an additional copy of each document to the rental unit and to any other address known to the person seeking possession as reasonably chosen to give actual notice to the defendant;  or

(2) If defendant is an artificial entity, pursuant to Sup. Ct. R. 57, by sending by certified mail or by sending by first class mail with certificate of mailing, using United States Postal Service Form 3817 or its successor, within 1 day after affixation, additional copies of each document to the rental unit and to the principal place of business of such defendant, if known, or to any other place known to the party seeking possession as reasonably chosen to effect actual notice.