iPhone users are slightly more likely to have updated to the latest OS version as compared to iPad users. The greatest difference being that iOS 5- equipped iPad users still generate close to 9% of total North American iPad Web traffic. The slightly lower adoption rate of iOS 7 is likely least partially due to features like AirDrop not coming to the iPad 2 or 3, minimizing the incentive for users of those devices to upgrade.
While still-active legacy devices make it unlikely for iOS 7 adoption to substantially surpass the nearly 90% adoption rate of iOS 6, the latest operating system will likely reach that point in a much quicker timeframe than its forerunner.
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