Yes, the OpenBack SDK handles all Provisional Push Notifications as long as the permissions are set properly by the developer.
As of iOS 12, notifications can be delivered quietly using Provisional Authorization before a user has given permission to receive notifications. When a notification is delivered quietly, it can only be seen in the iOS Notification Center, which the user accesses by swiping down from the top of their phone. They don't appear as banners or show up on the lock screen. As you might have guessed, quiet notifications also don’t make a sound.
Here is a guide that shows how to set up Provisional Authorization properly.