Mich. Comp. Laws § 211.31: Township board of review; completed roll valid; conclusive presumption.

Sec. 31.

Upon the completion of said roll and its endorsement in manner aforesaid, the same shall be conclusively presumed by all courts and tribunals to be valid, and shall not be set aside except for causes hereinafter mentioned. The omission of such indorsement shall not affect the validity of such roll.