Can I change Platform Notification callback URL to point to a new server?
You can make SetNotificationPreferences call as below to point your notification listener to a different URL. You do not need to do anything else , all the notification events that users have subscribed through your Application will be automatically associated to the new notification listener URL you have specified.
Keep in mind that the application callback URL is specific to a given application, so that Application Level Subscription and User Level Suscribtion must be associated with the same Developer Keys. When you make SetNotificationPreferences call you need to make sure :
The token used in SetNotificationPreferences request for setting notification URL must be generated from the same Application keys ( AppID, DevID and CertID), the keys that used to make User level suscription . Mixup keys and tokens would lead to a confusing issue.