Earlier, Microsoft had planned to have 1 billion devices running Windows 10 by 2018. Eventually they had to give up this ambitious goal last year and admitted that to get the 1 billion figure would take longer. . It is unclear exactly how long it will take since growth has stalled since Microsoft dropped the free Windows 10 upgrade package.
See also: If you don't hurry up, you can't upgrade to Windows 10 for free
Earlier this year, Microsoft unveiled a number of 500 million and confirmed that they would give up Windows Phone. Therefore, there will be less chance for mobile to contribute a part of the 1 billion devices running Windows 10.
Even so, Microsoft seems to have achieved its small goals. A source said earlier this year they targeted 550 million devices by the end of June and 575 million devices by the end of September. Now it has reached 600 million devices by the end of November, meaning that the set plan has been achieved. It is not clear when the milestone of 1 billion devices will be rolled.
See also: Microsoft announced a Windows security standard