A second developer beta of the iPhone 3.0 firmware should see testing open up for some of its most critical features, reports note. The beta, labeled build 7A259, is now being seeded to developers with the comment that they can immediately begin implementing applications with push notification. The technology exists as a substitute for background processes, and should allow apps such as instant messaging clients to signal users while otherwise inactive.

As the technology is dependent on Apple servers, the company is only gradually opening up live testing services, beginning with a few developers and expanding outwards. The same applies to in-app purchases, which have been given more detailed instructions for integration into new or existing software. Outside of the beta, the information should pass into an App Store Kit guide.

Developers are meanwhile said to state that many bugs have been eliminated from the original beta, and that the software runs substantially faster. Components addressed include Fonts, GameKit, MapKit, Bluetooth, text fields and the messaging interface. Apple is said to have told developers that tethering and MMS messaging will not be tested in any form during the public beta.