From which versions of Windows can you upgrade to Windows 8 and Windows Server 2012?

A quick post for today about Windows 8 and Windows Server 2012 upgrade paths. Here, I'm talking about the technical side regarding installations, not licensing.

Let's take Windows 8 first. Windows 8 can be upgraded from Windows 7 only, older versions like Vista and XP cannot be upgraded (you must do a clean install for Windows 8). On the hand, if you have Windows 7 (Starter, Home, Professional, etc.) you can do an in-place upgrade to Windows 8, retaining your applications and settings.

On the server-side, things are pretty much similar, except for one major thing: you cannot upgrade a 32-bit existing server to Windows Server 2012, which is 64-bit only. So, if you had, say, an older 32-bit Windows Server 2008 installation running, you cannot in-place upgrade that to Windows Server 2012. But if you had a 64-bit version of the same OS, then the upgrade would succeed.

For Windows Server 2012, you can upgrade from Windows Server 2008 and Windows Server 2012, but not from Windows Server 2003.

If you are interested in more details, check out this blog post and this topic (under section Upgrading previous retail versions) on Technet.