There is a roadmap leaked showing the planned releases of two new Windows Phone-based versions. Tango would be in the second quarter of 2012, should appear, while Apollo for the fourth quarter on the planning.
According to the roadmap, by WM Poweruser was published, Microsoft is going with Tango, especially trying to compete on price. Previously there were already rumors out that Microsoft with Tango devices the budgetmarkt wanted to operate to increase its market share
With Apollo, Microsoft focuses on high-end smartphones. In addition, the company expects that devices with this still unannounced version of Windows Phone to a higher volume to be produced. It is likely that the latest features with Apollo to be released, while Tango is a smaller update.
Microsoft released Windows Phone Mango in the fourth quarter of this year. Therefore, it seems that there is for the mobile OS two times a year a new version on the market. Microsoft has the existence of Tango and Apollo are not yet publicly confirmed, but would during a MSDN session about both versions.