JP Morgan analyst Mark Moskowitz has raised his estimates of iPhone shipments for the December quarter from 25.3 million units to 28 million. US carriers have reportedly been "surprised by the strong uptake" of the iPhone 4S, along with cheaper releases of the 4 and 3GS, which Moskowitz suggests will help Apple's penetration into poorer countries like China. Apple's best iPhone performance to date occurred during the June quarter, when it sold 20.34 million units worldwide.
