Windows 10 is making strides on desktop - it already makes up for more than 20% of the desktop OS market, having surpassed all Windows versions aside from the venerable Windows 7.

Windows 10 on mobile... well, fans might want to sit down. It has reached 14% of Windows phones and half of those are up to Windows 10 Mobile Anniversary Update. Growth is accelerating too. That's the good news.

So that's it then. Some phones can't be updated to 10. Those that are upgradeable, mostly haven't been. Why? Carriers running late with the update is one explanation but the more probable option is that people can update, they just don't care to. Neither option is particularly good for Microsoft's mobile efforts.
Windows on mobile has been steadily losing ground and while it's still the #3 phone OS, it's barely there. Last quarter, Android and iOS made up 99.1% of smartphone sales worldwide.

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