The Redmi Note 4 was just launched and the MIUI 8 based on Android N is already out for qualcomm version, however this is Beta ROM, not a stable version. If you have the Redmi Note 4 Qualcomm version you can try this ROM (note : this is beta may not be stable).
I have completed the Redmi Note 4 review, I was not satisfied with the camera quality. Yesterday I got an update and after the update there is a slight improvement, but not much. I will update the review later on.
Another advantage of getting a Redmi Note 4 is the Android Nougat update. In fact it is already ready going through the final beta testing. If you cannot wait for stable version you can try out the MIUI Android N 7.1.19 Global Beta version. Check the details here.
If you have bought the Redmi Note 4 do check the camera quality and do leave your feedback in comment section below.