Xiaomi has started issuing V12.0.2.0.RCXMIXM to the Redmi Note 8T, bringing Android 11 to the device globally. The update also contains MIUI 12 though, rather than MIUI 12.5 or MIUI 12.5 Enhanced Edition.
https://www.notebookcheck.net/Xiaomi-updates-the-Redmi-Note-8T-to-Android-11-globally-with-MIUI-12.575087.0.html