IOS Push Notification while device OFF or out of network - ios

I am developing an IOS app and I noticed that the notification arrives only when the device is ON and has internet access but if the device is OFF or out of network then NO notifications will be received.

Apple's Quality of Service https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html
It retains only one notification per application on a device:
Apple Push Notification Service includes a default Quality of Service
(QoS) component that performs a store-and-forward function. If APNs
attempts to deliver a notification but the device is offline, the QoS
stores the notification. It retains only one notification per
application on a device: the last notification received from a
provider for that application. When the offline device later
reconnects, the QoS forwards the stored notification to the device.
The QoS retains a notification for a limited period before deleting
it.

Related

Why does APNS deliver only last queued notification instead of all queued notifications?

Problem Statement : I'm using voip notification to show local notification.I'm trying to send notification from Apns to a offline device. So, It queued all pending notifications. But, It only send last queued notification once device becomes
online.
As per apple documentation Link
Quality of Service, Store-and-Forward, and Coalesced Notifications
Apple Push Notification service includes a Quality of Service (QoS)
component that performs a store-and-forward function. If APNs attempts
to deliver a notification and the destination device is offline, APNs
stores the notification for a limited period of time and delivers it
when the device becomes available again. This component stores only
the most recent notification per device and per app. If a device is
offline, sending a notification request targeting that device causes
the previous request to be discarded. If a device remains offline for
a long time, all its stored notifications in APNs are discarded.
To allow the coalescing of similar notifications, you can include a
collapse identifier within a notification request. Normally, when a
device is online, each notification request that you send to APNs
results in a notification delivered to the device. However, when the
apns-collapse-id key is present in your HTTP/2 request header, APNs
coalesces requests whose value for that key is the same. For example,
a news service that sends the same headline twice could use the same
collapse identifier value for both requests. APNs would then coalesce
the two requests into a single notification for delivery to the
device.

iOS. Send push to devices which are offline

I want to send push notification to app users. Users whom online will receive it immediately, right?. But what about users whom offline? Will they get notification after they become online?
Can you tell me more about than push notifications will de delivered?
Are messengers use pushes to send notifications about new messages?
Not possible in offline.
Check it: https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html
Apple Push Notification Service includes a default Quality of Service (QoS) component that performs a store-and-forward function. If APNs attempts to deliver a notification but the device is offline, the QoS stores the notification. It retains only one notification per application on a device: the last notification received from a provider for that application. When the offline device later reconnects, the QoS forwards the stored notification to the device. The QoS retains a notification for a limited period before deleting it.
If a device remains offline for a long time, all notifications that were being stored for it are discarded; when the device goes back online, none of the notifications are displayed.
Basically Apple will try to deliver the notification when the device will become online again (in a resonable time frame).
Apple Push Notification service includes a default Quality of Service (QoS) component that performs a store-and-forward function. If APNs attempts to deliver a notification but the destination device is offline, APNs stores the notification for a limited period of time and delivers it to the device when the device becomes available.
From https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html#//apple_ref/doc/uid/TP40008194-CH100-SW9

iOS PushKit (VoIP Push Notifications) Quality of Service

What is the PushKit QoS policy? The policy for the regular push notification is defined as store-and-forward.
Apple Push Notification service includes a default Quality of Service
(QoS) component that performs a store-and-forward function.
If APNs attempts to deliver a notification but the device is offline,
the notification is stored for a limited period of time, and delivered
to the device when it becomes available.
Only one recent notification for a particular app is stored. If
multiple notifications are sent while the device is offline, each new
notification causes the prior notification to be discarded. This
behavior of keeping only the newest notification is referred to as
coalescing notifications.
If the device remains offline for a long time, any notifications that
were being stored for it are discarded.
What about PushKit notification? Is it the same as for regular push notifications?
I performed the following steps to verify the issue myself
Put the device in airplane mode
Sent at least 5 different PushKit notifications
Wait for about 3 minutes
Cancel the airplane mode
Only the last PushKit notification arrived which is compatible with the store-and-forward Apple's policy (which is specifically defined for regular remote push notifications).

Can an iOS push notification selectively replace a prior notification?

I am using iOS push notifications. In Android you can set up to 4 notification keys and then using these keys you can have notifications replace prior notifications if they have not yet been read/seen by the user.
Do iOS push notifications also allow you to selectively replace prior notifications? (E.g. using a common notification key) or do they always "rack up" and cannot be replaced.
Link: Local and Push Notification Programming Guide:
Quality of Service
Apple Push Notification service includes a default Quality of Service
(QoS) component that performs a store-and-forward function.
If APNs attempts to deliver a notification but the device is offline,
the notification is stored for a limited period of time, and delivered
to the device when it becomes available.
Only one recent notification for a particular application is stored.
If multiple notifications are sent while the device is offline, each
new notification causes the prior notification to be discarded. This
behavior of keeping only the newest notification is referred to as
coalescing notifications.
If the device remains offline for a long time, any notifications that
were being stored for it are discarded.
There's no such mechanism in place in iOS.
After sending a push notification you have no control over it anymore.

What happens to push notifications after losing internet access?

What happens if an application is waiting for a push notification and the internet connection is unavailable?
For example, I tell my server to do task "A", and notify me via APNS when the task is ready. But, after I send the task to the server, the application loses internet connectivity.
Notification will be delivered when internet connection on iPhone becomes available again.
Apple Push Notification Service includes a default Quality of Service
(QoS) component that performs a store-and-forward function. If APNs
attempts to deliver a notification but the device is offline, the QoS
stores the notification. It retains only one notification per
application on a device: the last notification received from a
provider for that application. When the offline device later
reconnects, the QoS forwards the stored notification to the device.
The QoS retains a notification for a limited period before deleting
it.
See "Quality of Service" section of Local and Push Notification Programming Guide.
Be careful when sending PUSHes with own server API, and also take into account apns-expiration field in APNs Provider API payload.
This header identifies the date when the notification is no longer valid and can be discarded...
...if the value is 0, APNs treats the notification as if it expires
immediately and does not store the notification or attempt to
redeliver it...
By Apple.
It can be the reason, that the push notification does not come after network connection was restored.

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