Normally there should be a link to simply upload a PDF copy of your mid-year. You don’t need anything official until after accepting the offer of admission.
I was accepted recently and I had simply uploaded an updated transcript with my mid-year grades under the “Mid yr/second quarter grades” category of Minerva.
@coolkidmom D2 did the same thing; she uploaded an unofficial mid-year transcript and received her admission offer quite soon after that. It seems strange for them to wait for mid-year grades for kids who are way above the minima, imho, but it is of course their process!