MIUI 12 will be arriving on the Redmi Note 8T later this month, according to an official Xiaomi timeline. The commencement of the update may coincide with the release of MIUI 12 to the likes of the Redmi Note 7, Redmi Note 8 and the global version of the Redmi Note 9 Pro. There are reports of MIUI 12 finally reaching more Redmi Note 7 Pro handsets, too.
https://www.notebookcheck.net/MIUI-12-is-coming-to-the-Xiaomi-Redmi-Note-8T-this-month-as-reports-of-a-wider-rollout-for-the-Redmi-Note-7-Pro-mount.497759.0.html