The Redmi 4 - or 4X in some markets - is a 2017 phone thought to have been all but abandoned by its maker Xiaomi in software-update terms. Despite this, some users of the device in India have reported being able to install a new upgrade conferring the OEM's latest Android skin, MIUI 11. However, it seems this version is not based on Android 10, and has other drawbacks besides.
https://www.notebookcheck.net/The-Xiaomi-Redmi-4-reportedly-gets-MIUI-11-albeit-with-some-critical-caveats.443054.0.html