Okla. Stat. tit. 36, § 4210

There shall be a provision that unless the policy has been surrendered for its cash surrender value or unless the paid-up term insurance, if any, has expired, the policy will be reinstated at any time within two (2) years from the date of premium default upon written application therefor, the production of evidence of insurability satisfactory to the insurer, the payment of all premiums in arrears, and the payment or reinstatement of any other indebtedness to the insurer upon the policy, all with interest at a rate not exceeding six percent (6%) per annum compounded annually. Laws 1957, p. 386, § 4210.