Although the Android 8.1 Oreo update for the Xiaomi Mi A1 started to roll out last month, it was quickly stopped after the discovery of an SMS bug. Back then, most markets did not even receive it, so now it is the first time for most users of this successful Android One handset when the update reaches them.
https://www.notebookcheck.net/Android-8-1-Oreo-finally-available-for-the-Xiaomi-Mi-A1-in-Europe.316614.0.html