It may still be possible to install Windows 7/8.1 without seeing the error message below but unfortunately this isn't going to last. Skylake was also going to be included but this decision was eventually reversed (see thread above).
Intel have said they have no plans for supporting 7/8.1 with Kaby and even AMD are strangely quiet about the subject.
Below is the error message KB 4012982 which is seen if trying to use 7/8.1 with either Kaby or Rizen:
Symptoms
When you try to scan or download updates through Windows Update, you receive the following error message:
Unsupported Hardware
Your PC uses a processor that isn’t supported on this version of Windows and you won’t receive updates.
Additionally, you may see an error message on the Windows Update window that resembles the following:
Windows could not search for new updates
An error occurred while checking for new updates for your computer.
Error(s) found:
Code 80240037 Windows Update encountered an unknown error.
Cause
This error occurs because new processor generations require the latest Windows version for support. For example, Windows 10 is the only Windows version that is supported on the following processor generations:
Resolution
We recommend that you upgrade Windows 8.1-based and Window 7-based computers to Windows 10 if those computers have a processor that is from any of the following generations:
Intel have said they have no plans for supporting 7/8.1 with Kaby and even AMD are strangely quiet about the subject.
Below is the error message KB 4012982 which is seen if trying to use 7/8.1 with either Kaby or Rizen:
Symptoms
When you try to scan or download updates through Windows Update, you receive the following error message:
Unsupported Hardware
Your PC uses a processor that isn’t supported on this version of Windows and you won’t receive updates.
Additionally, you may see an error message on the Windows Update window that resembles the following:
Windows could not search for new updates
An error occurred while checking for new updates for your computer.
Error(s) found:
Code 80240037 Windows Update encountered an unknown error.
Cause
This error occurs because new processor generations require the latest Windows version for support. For example, Windows 10 is the only Windows version that is supported on the following processor generations:
- Intel seventh (7th)-generation processors
- AMD “Bristol Ridge”
- Qualcomm “8996"
Resolution
We recommend that you upgrade Windows 8.1-based and Window 7-based computers to Windows 10 if those computers have a processor that is from any of the following generations:
- Intel seventh (7th)-generation "Intel Core" processor or a later generation
- AMD seventh (7th)-generation (“Bristol Ridge") processor or a later generation
- Qualcomm “8996" processor or a later generation
