Most new APIs introduced since Vista are COM based, and after Windows 8, WinRT based (basically COM with IIinspectable, application identity, and .NET metadata instead of type libraries).

Plain old Win32 C API is basically frozen on Windows XP view of the world, although there are a couple of new .....ExNum() suffixes for stuff like HDPI or various IO improvements, the userspace drivers initially COM (UMDF), but reverted back to plain C struct with function pointers on version 2.0.