No. This is critical to understand. The Extended Kernel does not add DirectX 12 Ultimate, WDDM 2.0 graphics drivers, or modern Bluetooth stacks. It only adds . It makes the OS lie effectively enough that software doesn't crash during the initial compatibility check.
Microsoft does not sanction this. Modifying system files violates the EULA. The project exists in a legal gray area – it redistributes no copyrighted code (only patches), but applying patches to ntdll.dll is against Microsoft’s terms. Use at your own risk, for experimental/educational purposes. Windows 8.1 Extended Kernel