When an application for administration is filed, the court, or the probate registrar under informal administration proceedings, shall by order set a date as the deadline for filing a claim against the decedent's estate. The date shall be not less than 3 nor more than 4 months from the date of the order. If a claim is not filed by the deadline, the consequences provided in s. 859.02 apply.
Wis. Stat. § 859.01
The statute of limitations concerning claims filed against an estate in probate may not be waived. Estate of Palmer, 68 Wis. 2d 101, 227 N.W.2d 680 (1975).