Apple Seeds 4th Beta of iPhone firmware 2.1; Pulls Out Push Notification Service - iPhone HacksThe most likely explanation is that there are a lot of major bug fixes being packed into 2.1, and it's entirely reasonable to push features out to 2.2.
Apple has seeded developers of its iPhone Developer program with the fourth beta version of iPhone firmware 2.1. The latest update again consists of more bug fixes.
However, Apple has strangely pulled out the Push Notification Service APIs in this release for "further development".
The Push Notification APIs is Apple's solution for one of the features that we have been asking for, ability for native iPhone apps to run in the background especially for applications like Instant Messenger, Facebook etc...
On the other hand, Push Notification will also kill a lot of 40 cent SMS transactions. I've used Google Talk on my iPhone, and if were able to use push notification I'd use it all the time.
Those SMS transactions are a significant piece of AT&T and Apple's iPhone revenue. A $30/month tethering solution would make up for some of the loss, but not all.
So if I were Apple, all things being equal, I'd pull the Push and push the Tether.