Owners of the Xiaomi Mi Mix 2S, Mi Mix 3, Mi 8 Pro, and Mi 8 Explorer Edition smartphones can test out a version of Android 11 thanks to the team at Paranoid Android. The devs have frequently supported older Xiaomi devices with their custom ROMs, and now Paranoid Android Ruby is available as an initial dev release.
https://www.notebookcheck.net/Xiaomi-Mi-Mix-2S-Mi-Mix-3-Mi-8-Pro-and-Mi-8-Explorer-Edition-owners-can-now-try-out-Android-11-via-Paranoid-Android-Ruby-ROM.529914.0.html