Provisional notifications were released with iOS 12, intended as a way to help users deal with the deluge of notifications they receive on a daily basis.
With provisional push enabled, users won’t be asked to opt in or out of notifications for your app, they’ll automatically be opted in. However, these notifications will all be delivered “quietly”, meaning they won’t trigger a banner or sound and won’t appear on the lock screen, instead they’ll go straight to the Notification Centre. The Notification Centre is accessible with a swipe up from the lock screen as well as a downwards swipe from the top-left of an iPhone X or higher when the phone is unlocked.
Also note that any existing users who’ve opted in to your notifications won’t be affected by an update with provisional notifications switched on, they’ll continue to receive them in the same way they always have. Additionally, users who are receiving your pushes quietly are able to change them to be received prominently in the same way.
iOS now allows users turn off all notifications from an app, or set them to be delivered quietly, directly from a notification, and Siri will suggest doing so for apps whose notifications you rarely interact with. These tools are explicitly focused on reducing the number of pushes users receive every day. Provisional push not only exposes more users to your notifications, but also greatly reduces the chance of them falling victim to the above tools. Additionally, users who are receiving your pushes quietly are able to choose to receive them prominently both from the system settings and from the notification itself.
Apple are pushing this as the default approach to push notifications, and this has been mirrored by most of the major 3rd party push notification services. However, if you feel that provisional notifications aren’t right for you, let us know and we’ll discuss turning the functionality off in your update.