Seems like Apple is changing quite a few things for developers today. First they announced promo codes have gone international, now, as reported by iClarified, Apple apparently sent out a notification to some developers informing them that, starting December 22, Apple will improve the system behind the Push Notification Service to use more secure connections.
On December 22, 2010, the production Apple Push Notification service will begin to use a 2048-bit TLS/SSL certificate that provides a more secure connection between your provider server and the Apple Push Notification service.
To ensure you can continue to validate your server’s connection to the Apple Push Notification service, you will need to update your push notification server with a copy of the 2048-bit root certificate from Entrust’s website. This will not require a change to your iOS apps – this update only applies to provider servers.
Developers who have released apps that rely on push notifications will need to update their provider servers with the new certificate. More info available here.