Morgan Stanley analyst Katy Huberty says in a note to clients that a survey by her firm suggests the upgrade rate from older iPhones to the newer iPhone will be more than 50%, but not much more. Even 50% is considerably higher than the 18% upgrade rate found in a November 2008 survey and 25% since the launch of the original iPhone in 2007, notes “Fortune” (

A loyal and growing installed base is a good thing for Apple, Huberty says. She estimates that if 30% of current iPhone owners upgrade this year, Apple will sell 42 million units in 2010. If 50% upgrade, it will sell 48 million. In her model, the iPhone installed base rises from about 30 million at the end of 2009 to 100 million by the end of 2011.