The download of iOS 4.1 is free via iTunes for iPhone and iPod Touch owners.
Besides upgrades to new features for games, photos, and high-definition videos, Apple is using this software update to work out several bugs at the same time.
Apple said some issues it promises to fix with 4.1 include the proximity sensor problems that were causing some accidental dropped calls; the slow performance of the iPhone 3G with iOS 4.0; Bluetooth connectivity problems and other issues.
Other upgrades in iOS 4.1 include the ability to upload HD videos over Wi-Fi, TV show rentals on iTunes from an iPhone or iPod Touch, new HDR (high dynamic range) photo function and the delayed GameCenter.
GameCenter is a social-networking feature that allows iPhone and iPod Touch users to play games on their devices against friends in real time.
