APNS與GCM的推播能在Server保留多久

GCM

http://developer.android.com/google/gcm/adv.html#ttl

Setting an Expiration Date for a Message

The Time to Live (TTL) feature lets the sender specify the maximum lifespan of a message using the time_to_live parameter in the send request. The value of this parameter must be a duration from 0 to 2,419,200 seconds, and it corresponds to the maximum period of time for which GCM will store and try to deliver the message. Requests that don't contain this field default to the maximum period of 4 weeks.

APNS

http://stackoverflow.com/questions/8608849/how-long-does-a-push-notification-sit-in-queue-before-being-removed

Official developer documentation isn't clear about this. From developer.apple.com:

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.

But according to PCWorld, it's 28 days:

If the app is running, it gets the notification immediately. If the app isn't running, the notification is held in the phone to be consumed at the app's next launch. If the iPhone is offline when the sender attempts delivery, APNS attempts to send the notification for 28 days.

While 28 days may have been true in 2009, I wouldn't be surprised if its different today. The ambiguity in the documentation is a great excuse for Apple to change this timeout period willy-nilly.