Just got word of this today, thought I would share. Basically introducing a 10 round limit for detachable mags. Possession unlawful (i.e. NO Grandfather'd mags) and would result in a felony charge if not turned in by the said deadline.
https://www.revisor.mn.gov/bin/bldbill.php?bill=H0242.0.html&session=ls88
https://www.revisor.mn.gov/bin/bldbill.php?bill=H0242.0.html&session=ls88