Conn. Gen. Stat. § 4-150: Subpoenas and papers served upon or delivered to the Office of the Claims Commissioner.

(a) Any subpoena or other paper required to be served upon or delivered to the Office of the Claims Commissioner or to any person or official may be served or delivered in person or by certified mail. Service or delivery by certified mail shall be deemed complete upon the certification and deposit of such subpoena or paper at a United States post office. Proof of deposit and the return receipt shall be sufficient proof of service or delivery.

(b) Any such service or delivery required between the Office of the Claims Commissioner and any state agency or any state officer or employee may be made through the interdepartmental mailing system of the state, provided reasonable means are taken to ascertain that the subpoena or paper was received by the addressee.