David Smith shares the compelling reason why developers really need to stop worrying about updating support for iOS 4. It may sound cold, but the developer (his company makes a popular app called Audiobooks) uses his own user base for a non-scientific analysis of adoption of the latest versions of iOS:
This page presents data showing how quickly users are updating to new versions of iOS. The data below is taken from the user base of my Audiobooks apps. Audiobooks is universal so provides data for both iPhone and iPad. The free and paid versions of Audiobooks together get nearly 100k weekly downloads so provides a statistically meaningful data set. This data may not apply to your application’s user demographics but should give a good general sense of where users are.
He’s going to update the numbers every week, but right now iOS 4 is hovering around 8%. I wonder how many of those are devices that simply haven’t been updated (iPhone 4) versus devices that can’t (iPhone 3G).