This stock recovery file is required in order that it was possible to upgrade official MIUI via OTA (over-the-air). This means that case you’ve TWRP or any other custom recovery installed on your smartphone you can’t upgrade official MIUI via OTA. Upgrade process will simply fail. In order to proceed you need to install stock recovery and then proceed with update.
Stock Recovery for Xiaomi Redmi Note 4
ADB and Fastboot required.
Run CMD and type following commands:
adb reboot bootloader fastboot flash recovery redminote4_stock_recovery.img fastboot reboot