Microsoft .NET Framework 2.0 SP2 or compatible (3.5 SP1 which comes pre-installed with Windows 7 is sufficient)
Windows 10 is not currently supported.
CAFE-SDK
The required SDK version can be found on the Middleware Version Table on the Nintendo Developer Portal or in the Unity for Wii U download description on the Downloads page.
GHS Multi (Compiler, Linker, Debugger Software)
The required version can be found in the Unity for Wii U download description. You can find this on the Downloads page on Nintendo Developer Portal.
Unity for Wii U
The Unity for Wii U license can be found in the Unity for Wii U download description. You can find this on the Downloads page on Nintendo Developer Portal.
If you are doing a manual installation (not using the Nintendo Dev Interface) keep these in mind:
CONFIDENTIAL