Developers downloading the third beta of Apple's iOS 4.1 , which became available yesterday evening, were disgruntled to find that in this release, Apple's dropped support for both the iPhone 3G and the second generation iPod Touch. The changes were made to Apple's Game Center, a social network centered are iOS games and its accompanying GameKit APIs.

The Game Center has been presented as one of the central changes in iOS4 since it was first announced in early April. New GameKit classes will allow developers functionality that includes technology for matching groups of users based on various criteria and in-application voice chat. On the player side, Game Center allows players to log in with their Apple ID in order to view score boards and achievements as well as to challenge other players and see what their friends are playing. The ability to match skill level will allow players to pick opponents who present a worthy challenge.

It still looks as though the Game Center and GameKit will make it into the release, but the limitations make it less useful to developers who want to tap the market of older devices. Indeed, Apple seems to be anticipating obsolescence with the decision to drop support for the second generation iPod Touch, which is still available for purchase.

The decision may be intended to force users to upgrade, particularly with the fourth generation of the iPod touch scheduled for release this fall.

Other features of iOS 4 include a control panel for location permissions on an app-by-app basis, the ability to encrypt e-mail using the iPhone's PIN code, CoreMotion to allow developers to use the iPhone 4's new Gyroscope, and support for limited multi-tasking in third-party applications. Over 1500 new APIs will become available to developers in the release.