We already know that Windows 10 will be out by the end of the year and that there will be Windows 10 Technical Review any time soon but we do not know that Microsoft is putting enormous efforts with the goal of finishing the new OS as soon as possible. In fact according to certain online sources Windows 10 RTM may be done and out in June 2015.
There is no official confirmation of this news by Microsoft as of now but in the past years Microsoft has been releasing new versions of Windows in the fall. Thus Windows 7 came out on October 22, 2009, while Windows 8 did the same on October 26, 2012. Analysts now believe that Windows 10 will come out in the summer of 2015 so that PC vendors and manufacturers can have their products ready by the beginning of the back-to-school season. In addition Microsoft has patented the “Windows 365” trade name, which hints that Microsoft may soon unveil a subscription model for Windows.
Windows 10 will be a free upgrade for people who run Windows 7, Windows 8 and Windows 8.1 for one year after the release of the new OS.
Source: Techspot.com