Okla. Admin. Code § 590:25-9-5
If the Participant continues employment after attaining such applicable age as set forth under the federal Internal Revenue Code Section 401(a)(9)(C)(v), all benefits payable under the Plan may be deferred until the Participant retires, terminates employment, dies or when the Participant is faced with an unforeseeable emergency. If the Participant is not an active State employee, the payment of benefits must begin no later than April 1 of the calendar year following the calendar year in which the Participant attained such age as set forth under the federal Internal Revenue Code Section 401(a)(9)(C)(v). Roth Elective Deferral Subaccounts and Roth Rollover Contribution Accounts are not subject to the requirements of Section 401(a)(9)(A) of the federal Internal Revenue Code. No additional deferral under this Plan may be made by the Participant after termination of employment.
Okla. Admin. Code § 590:25-9-5