If you own any of the following devices, you can now install a public beta version of MIUI 10 (China Developer ROM) on your phone.
The devices are the Mi 8, Mi 8 SE, Mi 6, Mi MIX 2S, Mi MIX 2, Mi MIX, Mi Note 2, Redmi S2 and Redmi Note 5. The Mi 6X should be among but the update has been pulled down due to an unresolved issue with the camera. Once it is fixed, it will be made available.
MIUI 10 China Developer ROM 8.6.1x brings a number of new features including a new navigation experience for full-screen phones, redesigned recent apps screen, an AI assistant and more.
Depending on your device, the update is about 2GB to 2.7GB. You can check the source link for steps on how to get the update. Xiaomi says it will soon begin recruiting beta testers for the second batch of supported devices.