Not sure if this has been posted or not, but if you plan to actually use the upgrade option, these are the paths you can take.
- No upgrade options for Windows Vista Starter (SP1, SP2), not even to Windows 7 Starter;
- Windows Vista Home Basic (SP1, SP2) 32-bit (x86) and 64-bit (x64) can be upgraded to Windows 7 Home Basic, Home Premium and Ultimate 32-bit (x86) and 64-bit (x64);
- Windows Vista Home Premium (SP1, SP2) 32-bit (x86) and 64-bit (x64) can be upgraded to Windows 7 Home Premium and Ultimate 32-bit (x86) and 64-bit (x64);
- Windows Vista Business (SP1, SP2) 32-bit (x86) and 64-bit (x64) can be upgraded to Windows 7 Professional, Enterprise and Ultimate 32-bit (x86) and 64-bit (x64);
- Windows Vista Enterprise (SP1, SP2) 32-bit (x86) and 64-bit (x64) can be upgraded to Windows 7 Enterprise 32-bit (x86) and 64-bit (x64);
- Windows Vista Ultimate (SP1, SP2) 32-bit (x86) and 64-bit (x64) can be upgraded to Windows 7 Ultimate 32-bit (x86) and 64-bit (x64);
- No upgrade options for Windows Vista Home Basic N (SP1, SP2), not even to Windows 7 N or E;
- No upgrade options for Windows Vista Business N (SP1, SP2), not even to Windows 7 N or E.
- Since a clean install is REQUIRED for XP upgrades, XP users can choose any of the levels of Windows 7, regardless of the level of their current XP.
When it comes down to Vista-to-Windows 7upgrades, “Cross-architecture in-place upgrades (for example, x86 to x64) are not supported. Cross-language in-place upgrades (for example, en-us to de-de) are not supported. Cross-build type in-place upgrades (for example, fre to chk) are not supported. Cross-media type in-place upgrades (for example, Staged to Unstaged or Unstaged to Staged) are not supported,” Microsoft reveals.
In short, you can upgrade up a level, but not down a level. You can do a clean install with the upgrade media though as stated.
For Windows 7 Milestones, Microsoft has revealed that:
- Windows 7 M3 to Windows 7 Beta in-place upgrade is supported;
- Windows 7 M3 to Windows 7 RC in-place upgrade is NOT supported;
- Windows 7 M3 to Windows 7 RTM in-place upgrade is NOT supported;
- Windows 7 Beta to Windows 7 RC in-place upgrade is supported;
- Windows 7 Beta to Windows 7 RTM in-place upgrade is NOT supported;
- Windows 7 RC to Windows 7 RTM in-place upgrade is supported.