If You’re Still Running iOS 3.1.3, You Can No Longer Download Applications Directly From The App Store Application

Since December 16, Apple fans still rocking an iPhone or iPod touch on iOS 3.1.3 have been unable to download iOS applications directly from the App Store. Instead, iOS device owners stuck running iOS 3.1.3 must purchase and download applications in iTunes and sync them across to their iPhone or iPod touch.