Mobile device fragmentation is a phenomenon that occurs when some mobile users are running older versions of an operating system, while other users are running newer versions.
Mobile device fragmentation is often made worse when the wireless carrier, and not the device manufacturer, is in charge of deciding when to deploy operating system updates. Mobile device fragmentation can be a problem for software developers who must create different versions of the same app in order to make sure it works correctly with different versions of a given OS. It can also be a problem for IT departments because different operating versions have different capabilities, which can make them harder to manage and secure.
The term mobile device fragmentation is also used to describe different versions of the same operating system that are created when an original equipment manufacturer (OEM) modifies an open source mobile operating system for specific products.