(a) Service of legal process upon any partnership which has not filed a statement of partnership existence, a statement of qualification or a statement of foreign qualification and which is formed under the laws of the State of Delaware or doing business in the State of Delaware shall be made by delivering a copy personally to any partner doing business in the State of Delaware or by leaving it at the dwelling house or usual place of abode in the State of Delaware of a partner or at a place of business of the partnership in the State of Delaware. Service by copy left at the dwelling house or usual place of abode of a partner or at a place of business of the partnership in the State of Delaware, to be effective, must be delivered thereat at least 6 days before the return date of the process, and in the presence of an adult person, and the officer serving the process shall distinctly state the manner of service in the return thereto. Process returnable forthwith must be delivered personally to the partner.

(b) In case the officer whose duty it is to serve legal process cannot by due diligence serve the process in any manner provided for by subsection (a) of this section, it shall be lawful to serve the process against the partnership upon the Secretary of State, and such service shall be as effectual for all intents and purposes as if made in any of the ways provided for in subsection (a) of this section. Process may be served upon the Secretary of State under this subsection by means of electronic transmission but only as prescribed by the Secretary of State. The Secretary of State is authorized to issue such rules and regulations with respect to such service as the Secretary of State deems necessary or appropriate. In the event that service is effected through the Secretary of State in accordance with this subsection, the Secretary of State shall forthwith notify the partnership by letter, directed to the partnership at the address of any partner or the partnership as it is furnished to the Secretary of State by the person desiring to make service. Such letter shall be sent by a mail or courier service that includes a record of mailing or deposit with the courier and a record of delivery evidenced by the signature of the recipient. Such letter shall enclose a copy of the process and any other papers served on the Secretary of State pursuant to this subsection. It shall be the duty of the plaintiff in the event of such service to serve process and any other papers in duplicate, to notify the Secretary of State that service is being effected pursuant to this subsection, and to pay the Secretary of State the sum of $50 for the use of the State of Delaware, which sum shall be taxed as part of the costs on the proceeding if the plaintiff shall prevail therein. The Secretary of State shall maintain an alphabetical record of any such service setting forth the name of the plaintiff and defendant, the title, docket number and nature of the proceeding in which process has been served upon the Secretary of State, the fact that service has been effected pursuant to this subsection, the return date thereof, and the day and hour when the service was made. The Secretary of State shall not be required to retain such information for a period longer than 5 years from the Secretary of State’s receipt of the service of process.

72 Del. Laws, c. 151, § 1; 70 Del. Laws, c. 186, § 1; 77 Del. Laws, c. 289, § 5.