Xiaomi has announced that Redmi Note 8 Pro devices operating on the China MIUI 12 ROM will start receiving a new beta stable update of the Android overlay via OTA. For the moment, only random users of the Redmi Note 8 Pro will get the new MIUI 12 update, which brings the October 2020 security patch with it.
https://www.notebookcheck.net/Redmi-Note-8-Pro-receives-new-MIUI-12-beta-stable-update.504216.0.html