Mid Year Reports showing any recent grades that are available before mid-February are required for applicants whose decision has been postponed. If the Mid Year Report is required to complete the review of your application, you may log in to Enrollment Connect to verify the receipt of the grades.

However, you are not required to have your high school counselor submit the Mid Year Report unless you are notified by the Office of Undergraduate Admissions via Enrollment Connect that we will need these grades.

https://umich.custhelp.com/app/answers/detail/a_id/79/~/mid-year-report

(I'm not sure whether this is current info, but there it is.)