getting push notifications delivered to iPhone simulator when CloudKit changes

I have a shopping list app that shares a list of Product records between users. The app on my phone shared its private database with another user account (running on a simulator) which accepted it. Both devices can see changes from the other if the device does a full refresh from iCloud. Now I want to have the app on the devices be notified when the other changes/adds/deletes a Product record. I did the following to get push notifications to work (but haven't been successful yet)

I have enabled background fetch and remote notifications in my app capabilities.

The app registers for remote notifications with UIApplication.shared.registerForRemoteNotifications() and receives the didRegisterForRemoteNotificationsWithDeviceToken callback.

The app sets a subscription with CKModifySubscriptionsOperation for the "Product" recordType. I set the QoS to .utility on the appropriate private or shared database.

However, when I add a Product record on my record, the didReceiveRemoteNotification callback doesn't execute.

What am I missing?