As part of Stable update which are rolled out for the all users, MIUI 8 Global Stable Version V8.2 based on Android Nougat for Mi 5 has been relaesed to users. if you are on stable ROM you will get update via OTA i.e. Settings>About phones>System Updates and in case the update has not reached you or you are impatient then here are the links......to download the ROM.
Note: To update it manually please go to "Updater" and choose full package zip file to upgrade. If you are updating from other ROMs, please don't forget to back up and wipe all data before flashing to avoid data conflicts. Use Clean All option in the new Mi Flash Beta Tool while flashing to perform a full wipe and fresh install.
I want to report here that V8.2.2 hasn't fixed the Google Playstore issue of "Waiting for Network". Check the screenshots. I am also not so sure why Playstore shows Mi5 as uncertified device. Please clarify.