Okla. Stat. tit. 68 § 2379
This act shall not release, extinguish or otherwise affect the liability of any person or property for taxes that shall have accrued, or become payable or owing, under any law repealed by this act, and which shall have not been paid when this act becomes effective. All such taxes shall remain payable and be subject to the laws levying same to the same extent as if this act had not been enacted, and when collected shall be apportioned or distributed as provided by such laws. All remedies for the collection of unpaid taxes, existing or available when this act becomes effective, shall be available for the collection of taxes due under such prior laws or due under this act, and this act shall not affect any proceeding or action commenced before the effective date hereof, or any proceeding or action pending when this act becomes effective.
Okla. Stat. tit. 68, § 2379