News didn't tell me how Xiaomi manage to choose the date but all i know so far is that 27 Xiaomi smartphones will be updated to MIUI 9 today Dec 27th. Xiaomi announced a few other Mi phones can upgrade to MIUI9. Those models include the Xiaomi Mi 3, Redmi Note 2, and Redmi Note 3.
How to upgrade Xiaomi Android Smartphone OS to MIUI 9
- Firstly, you should get a notification that an OTA update is available for your device. Make sure you are not rooted before you update.
- Secondly, you can go to settings>>About phone> and miui version. Click on update to check for update.
- Finally, you can go to MIUI forum here, download the rom and update your device to the latest MIUI 9.