According to the latter information the upcoming ones Windows 9 will probably be called Windows TH and will be available for free to Windows 8 / 8.1 users.
First, the Windows 9 will be presented for the first time (Technical Preview) on September 30 and according to The Verge, the name of the functional will be Windows TH (probably from the code name Threshold) as it appeared here (link no longer works) and is shown in the figure below.
Also, as shown in the picture, a new program called Windows Insider will start to give users various builds of the operative, so that they give the appropriate feedback, with the link to the service is not active.
According to the president of Microsoft Indonesia, Andreas Diantoro, The Windows 9 will be available free as a upgrade to those who have bought them Windows 8 / 8.1.
Users will download it installer from the Microsoft site and will upgrade their function in the new edition, just as it has been for years Apple with Mac OS X.
Also, Microsoft is seeing that many still use them Windows XP, potentially tempting them to upgrade to the new one with one very low price disposal.
Source: e-pcmag.gr
