Windows 7 is "version 6.1.7000" but for a reason

When you go to the traditional DOS console, using the command "cmd", and type the command "ver" at the prompt, you find out that Windows 7 is actually "version 6.1.700" and the main reason being compatibility issues. In other words, if you want to run in Windows 7 a program, which is compatible with Vista (i.e. Windows 6.0 version) it may not run. Some applications did not run in Vista simply because they were designed for Windows 5.x and perhaps other reasons. However, as Mike Nash explains in his excellent blog, there's been some fodder about whether using 6.1 in the code is an indicator of the relevance of Windows 7. It is not. Windows 7 is a significant and evolutionary advancement of the client operating system. It is in every way a major effort in design, engineering and innovation.