There was a time when a smartphone could earn the title “flagship” with just a quad-core Snapdragon 820, 3 GB LPDDR4 RAM, 32 GB UFS 2.0 storage, a 3,000-mAh battery, and a rear-facing main camera setup that featured a single 16 MP lens. The Xiaomi Mi 5, which was released in 2016, originally came running on Android 6.0 Marshmallow and was eventually upgradeable to Android 8.0 Oreo/MIUI 10. But thanks to a custom ROM in the form of LineageOS 18.0, that is not the end of the story for the Mi 5.
The same can be said for the equally vintage Xiaomi Mi 5s Plus. This device came with a dual-camera setup, a Snapdragon 821, and up to a pretty beefy 6 GB RAM. There will be plenty of happy owners around the world who still use this decent smartphone, and once again thanks to LineageOS 18.0, users can get to try out an Android 11-based operating system on their favored smartphone.
The support page over at XDA Developers for the Xiaomi Mi 5 states that basically everything works, and all configurations of the Mi 5 are supported by this particular LineageOS 18.0 custom ROM. The software is in a beta phase though, so glitches and bugs should be expected. As for the Mi 5s Plus ROM, which is not the same as the one for the Mi 5, this is in a testing phase and the Wfd Service does not work with this build. Make sure to save all your data before installing either of these ROMs.
Source(s)
XDA Developers (1/2) via XiaomiAdictos (in Spanish)