Apple has released the latest version of its new iPhone software to developers on Tuesday opening up its Push Notification service as promised.

The new update, labelled iPhone OS beta 2 build 7A259 for those looking for the pub quiz answer, improves speed and performance as well as allowing developers to slowly get to grips with the notification service, that allows them to send messages from an app to the user if they are in another application.

According to Appleinsider, who broke the news "developers were also provided with more detailed information on how to build in-app purchasing functionality into their existing or future applications. Much of this technical information will reportedly appear in a App Store Kit reference guide".

Apple has also reportedly confirmed that MMS messaging and device tethering won't be supported at all during the iPhone 3.0 beta test.

Apple announced that the iPhone would be getting a new software update sometime over the summer (expected in June) allowing users to access of a host of new features including copy, cut and paste.