The Xiaomi Mi 5 and Mi 5s Plus smartphones have recently gained support from LineageOS 18.0, which is firmware based on Android 11. Both the Mi 5 and Mi 5s Plus were released in 2016, and being able to utilize an Android 11-based custom ROM will help keep them relevant for users who don't want to upgrade their device.
https://www.notebookcheck.net/Xiaomi-Mi-5-and-Mi-5s-Plus-stay-relevant-thanks-to-Android-11-based-LineageOS-18-0-custom-ROMs.496925.0.html