On my Mi Note 3 (Jason), 8.9.20 is running just fine. I haven't yet found any bug that bothers me really, except for the fact that Mi Cloud Backups do not work anymore. In 8.9.6 that I had before, this worked fine, but synchronizing the gallery didn't work. This apparently still doesn't work (or is extremely slow). Nor is the long-standing Bluetooth bug fixed. But apart from this, I am happy with 8.9.20 so far.