I'm running into the same issue of the callback not being called on swift.

Thanks for your reply. You do have local copies of the content, right? Yes, I have local copies that I originally wrapped into an IAP and uploaded to the App Store. I can roll them into the app itself as an on-demand resource and download them after the purchase/restore. But I'm not sure if I have to remove the hosted content from the App Store to prevent any issues. so I'm wondering what the process is for migrating to on-demand resources. There is no automated process. Do you know of example code before/after moving from hosted content to on-demand resources?