The first rumored to be releasing Windows update called Windows Blue and may arrive this summer in the form of upgraded Windows 8, while the second is Windows 8 will have a newer version replace the Windows 9.
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As usual, Microsoft is not talking about future projects, so there is no confirmation on this, but sources claim that Windows 9 will most likely appear in the beginning of next year.
According to a recent report, Microsoft will release the first Windows 9 beta on January 7, 2014, while the first release candidate possibly in July 2014. If everything goes according to plan, Windows 9 RTM can be completed in October 2014, while the public release will take place in November.