Iowa Code § 488.117

1. A registered agent for service of process appointed by a limited partnership or foreign limited partnership is a registered agent of the limited partnership or foreign limited partnership for service of any process, notice, or demand required or permitted by law to be served upon the limited partnership or foreign limited partnership.

2. If a limited partnership or foreign limited partnership does not appoint or maintain a registered agent for service of process in this state or the registered agent for service of process cannot with reasonable diligence be found at the registered agent’s address, the secretary of state is an agent of the limited partnership or foreign limited partnership upon whom process, notice, or demand may be served.

3. Service of any process, notice, or demand on the secretary of state may be made by delivering to and leaving with the secretary of state duplicate copies of the process, notice, or demand. If a process, notice, or demand is served on the secretary of state, the secretary of state shall forward one of the copies by certified mail or restricted certified mail to the limited partnership or foreign limited partnership at its registered office.

4. Service is effected under subsection 3 at the earliest of any of the following:

a. The date the limited partnership or foreign limited partnership receives the process, notice, or demand.

b. The date shown on the return receipt, if signed on behalf of the limited partnership or foreign limited partnership.

c. Five days after the process, notice, or demand is deposited in the mail, if mailed postpaid and correctly addressed.

5. The secretary of state shall keep a record of each process, notice, and demand served pursuant to this section and record the time of, and the action taken regarding, the service.

6. This section does not affect the right to serve process, notice, or demand in any other manner provided by law.