Okla. Stat. tit. 58 § 385c
If it appears to the court, from such verified petition and the evidence that it is necessary and for the best interest of said estate to mortgage the whole of such real estate or any part thereof, except the homestead, for the purposes and reasons herein set forth, the county judge of the district court shall by order set a time for hearing the petition and shall give and issue notice thereof and cause copies of such notice to be mailed to each of the heirs at law, devisees, and legatees of the decedent, whose addresses are known, at least fifteen (15) days prior to such hearing, and shall cause notice thereof to be published in a newspaper of general circulation in the county where said hearing is to be held for two (2) weeks in a weekly paper, or ten (10) days in a daily paper, prior to such hearing. The notice shall contain a description of the property sought to be mortgaged, the amount of the proposed mortgage and the purpose or purposes therefor.
Okla. Stat. tit. 58, § 385c