Wis. Stat. § 851.70: Presumption in favor of orders.

When the validity of any order or judgment of a circuit court in a probate proceeding or certificate to terminate a life estate or joint tenancy in a death tax proceeding is drawn in question in another action or proceeding, everything necessary to have been done or proved to render the order, judgment or certificate valid and which might have been proved by parole evidence at the time of making the order or judgment and was not required to be recorded shall, after 20 years from that time, be presumed to have been done or proved unless the contrary appears on the same record.