Because Apple lets users upgrade to the latest version of iOS on all compatible devices on the day its released, the adoption rate is naturally higher than on Android -- where carriers generally decide when or if a given device will receive updates on a model-by-model basis, and have a natural incentive to limit the upgradability of a device. Even so, reports that iOS 6.1 -- released on Monday -- is already installed on more than 22 percent of all compatible iOS devices represents the fastest uptake of a system update ever.
