More than four years after it launched running Android 7, the Xiaomi Mi A1 lives on thanks to the community support it has been receiving ever since. Although it gets no more official security patches and the latest major Android update is Pie, a few Android 12-based ROMs are already available for this popular smartphone.
https://www.notebookcheck.net/Multiple-Android-12-ROMs-available-for-the-four-year-old-Xiaomi-Mi-A1.583671.0.html