APN (Apple Push Notification) payload size limit

Question

In official documentation you can find the info:

Each push notification includes a payload. The payload contains information about how the system sh

Answer 1

For iOS 9 there are some changes:

Introduction of HTTP/2
Payload increased to 4KB

4 KB limit apply to all versions of iOS and OS 10

Check this official link

• For regular remote notifications, the maximum size is 4KB (4096 bytes)

• For Voice over Internet Protocol (VoIP) notifications, the maximum size is 5KB (5120 bytes)

• If you are using the legacy APNs binary interface to send notifications instead of an HTTP/2 request, the maximum payload size is 2KB (2048 bytes)

Check this video link for more details regarding the features of HTTP/2
https://developer.apple.com/videos/play/wwdc2015-720/