What is the maximum length of a Push Notification alert text?

Question

What is the maximum length of the alert text of an iOS push notification?

The documentation states that the notification payload has to be under 256 bytes in total,

Answer 1

According to updated Apple document (check my answer date):

"... When using the HTTP/2 provider API, maximum payload size is 4096 bytes. Using the legacy binary interface, maximum payload size is 2048 bytes. Apple Push Notification service (APNs) refuses any notification that exceeds the maximum size."