Okla. Stat. tit. 36, § 36-4805: Proofs of loss - Conditions of enforcement of limitation

of time.

When any insurance policy subject to the provisions of this

article contains a provision that the insured must render a written

sworn proof of loss within sixty (60) days from the date of fire or

loss to the insurer, or the same is required by law to be so

rendered, the insurer cannot assert the failure of insured to so

render such proof of loss in any litigation or court proceeding,

unless the insurer plead and prove that it has furnished the insured

with two blank forms for the execution of proof of loss, that has

printed thereon, in bold-faced type in a conspicuous place, the

warning that a proof of loss must be rendered to the insurer within

sixty (60) days from the date of receipt of the blank forms for

proof of loss by the insured, or by putting such warning in a like

form in a letter of instruction for executing a proof of loss that

will accompany the proof of loss blanks furnished the insured, and

the insurer has further executed and furnished the insured its

written extension of time, giving the insured sixty (60) days from

the date such blanks were received by the insured. These

requirements cannot be waived by any agreement between the parties

or otherwise.