Windows 7: Windows 8 New Logo Confirmed by Microsoft

The decision to use the name Windows 7 is about simplicity. Simply put, this is the seventh release of Windows, so therefore Windows 7 just makes sense. Coming up with an all-new 'aspirational' name does not do justice to what we are trying to achieve, which is to stay firmly rooted in our aspirations for Windows Vista, while evolving and refining the substantial investments in platform technology in Windows Vista into the next generation of Windows.[9][10]

The very first release of Windows was Windows 1.0, the second was Windows 2.0, the third Windows 3.0. Here's where things get a little more complicated. Following Windows 3.0 was Windows NT which was code versioned as Windows 3.1. Then came Windows 95, which was code versioned as Windows 4.0. Then, Windows 98, 98 SE and Windows Millennium each shipped as 4.0.1998, 4.10.2222, and 4.90.3000, respectively. So we're counting all 9x versions as being 4.0. Windows 2000 code was 5.0 and then we shipped Windows XP as 5.1, even though it was a major release we didn't want to change code version numbers to maximize application compatibility. That brings us to Windows Vista, which is 6.0. So we see Windows 7 as our next logical significant release and 7th in the family of Windows releases...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. The only thing to read into the code versioning is that we are absolutely committed to making sure application compatibility is optimized for our customers.[12]