Okla. Stat. tit. 40 § 2-507
Notice of a determination upon a claim shall be given promptly to the claimant by delivery thereof or by mailing the notice to the claimant's last-known address or by electronic means if the claimant elected this form of notification through procedures set out by Oklahoma Employment Security Commission rules. Notice of a determination shall also be given promptly to the last employer of the claimant, for whom the claimant worked at least fifteen (15) working days, that objected to the claim in accordance with the provisions of subsection E of Section 2-503 of this title and to each other employer who timely filed a written objection to the claim. If the employer has elected to be notified by electronic means according to procedures set out in Oklahoma Employment Security Commission rules, notice shall be deemed to be given when the Commission transmits the notification by electronic means.
Okla. Stat. tit. 40, § 2-507