I was thinking today about the various user-agents that IE8 will use depending on the operating system it is on. According to the IEBlog it will vary depending on the version (Vista or Windows 7) and whether it's 32-bit or 64-bit including whether it's a 32-bit IE8 running on 64-bit Windows.Now what I didn't spot at first was that the user-agent for Windows 7's IE8 is Windows 6.1. It's perfectly acceptable that the next version of Windows is 7 as I understand that Windows 95 (version 4) was pretty much the same as 98 and ME's code bases. Which is why I found them calling it Windows 6.1 in the user-agent to be quite odd. They do provide a link to the Windows blog however to explain this. The key to their reasoning behind calling it 6.1 comes from just two paragraphs:
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.
We learned a lot about using 5.1 for XP and how that helped developers with version checking for API compatibility. We also had the lesson reinforced when we applied the version number in the Windows Vista code as Windows 6.0-- that changing basic version numbers can cause application compatibility issues.
It's a bit mad in my opinion, if something is version 7 then it's version 7 - not 6.1. They should pick one or the other and not both. It should be the job of application makers to not rely on Windows version numbers.
