The European variant Redmi Note 9S is receiving the update with MIUI 12 firmware version V12.0.3.0.QJWEUXM. The update is currently rolling out as European ROM. The company will soon roll out the update to other regions as well.  You can manually check the software update on your device whether it’s available on your device or not. Head over to the device Settings –> About Phone –> Check for Software Update. 

MIUI 12.0.3.0.QJWEUXM Update Changelog:

[System]

Optimization: Updated Android Security Patch to January 2021. Increased system security.

Download MIUI 12.0.3.0 (EEA Stable)

Recovery ROM || OTA from 12.0.2.0

Manul Installation

Download the firmware file and save that in your device Now follow the guide given below to install the ROM manually (follow the recovery ROM (zip) guide) How To Install Stock Firmware OTA Update Zip / Fastboot Files On Xiaomi Devices
V12 0 3 0 QJWEUXM   Redmi Note 9S January 2021 security patch  Europe Stable ROM  - 52