As promised, Microsoft has released the Windows 10 ROM for the LTE variant of the Xiaomi Mi 4. The ROM is part of Microsoft’s Windows Insider program and although stable enough to be installed could have some bugs still.
The ROM currently is only compatible with the LTE variant of the device and it is not recommended to install it on any other variant. Once installed, you can expect the full Windows 10 experience devoid of any Xiaomi influence as this is coming straight from Microsoft.
The ROM with instructions can be found in the link below.