After spending the last few months available on HBO Max, the Harry Potter films will migrate to Peacock as part of Warner Brothers’ deal with NBC Universal. All eight films will leave HBO Max on August 25 as scheduled, then premiere on Peacock in October. It gets a little murky after that.
The films will remain on Peacock for a month, then disappear again until 2021. At that point, they will be available in a limited six month window on Peacock. Vulture reports that Warner and NBC are considering a deal that would see the movies ping-ponging back and forth between the two services until 2025, which is when the original deal that gave NBC the broadcast rights is scheduled to end.
Unlike HBO Max, the Potter films will be free (though ad-supported) on Peacock. Peacock itself has both a free and premium tier, with the free tier including ads and the premium tier featuring no ads and extra content. You can find more info about the service here.