A reported update policy operated by Xiaomi in regard to MIUI and Android upgrades has shown the smartphone series favored by the Chinese OEM and which are more likely to be neglected. The unofficial list reveals that owners of Redmi (not Redmi K), Redmi Note, POCO M, and POCO C smartphones will receive the least upgrades.
https://www.notebookcheck.net/Xiaomi-s-unofficial-update-policy-gives-short-shrift-to-the-Redmi-Redmi-Note-and-POCO-C-series.499227.0.html