With Windows 10, Microsoft is changing the way it delivers updates to Windows users. Microsoft will provide new features and functionality over time. They will keep updating the OS till the lifetime of the device. They are calling it Windows as a Service. Due to these changes, they have a new revenue recognition model. Since Windows 10 will include software upgrades provided over time, rather that at specifically priced software upgrade events, it will result in the deferral of revenue.
Recently, they detailed the new revenue recognition model. Take a look at it above.