Mich. Ct. R. 1.112
As amended through May 22, 2024
If filed by an unrepresented individual who is incarcerated in a prison or jail, a pleading or other document must be deemed timely filed if it was deposited in the institution's outgoing mail on or before the filing deadline. Proof of timely filing may include a receipt of mailing, a sworn statement setting forth the date of deposit and that postage has been prepaid, or other evidence (such as a postmark or date stamp) showing that the document was timely deposited and that postage was prepaid.
Mich. Ct. R. 1.112