Xiaomi will be celebrating its 8th anniversary at an event to be held on May 31 and to spice things up, the company will not only launch its newest flagship handset in Xiaomi Mi 7 (or Mi 8, whatever the name) but also the successor to the MIUI 9, which, of course, is called MIUI 10.
In fact, the Chinese OEM has already opened the gates for registrations, but so far, the software is limited to the beta testing program.
You are probably asking whether your current Xiaomi device is eligible for MIUI 10. Well, Xiaomi has given out a full list of devices that are expected to get the new skin, with some already receiving the update while others are being lined up for the same. From the look of things, it seems only devices running Android Marshmallow and above will qualify for this update, as listed below.
Xiaomi Mi 6, Mi 6X, Mi 5, Mi 5S, Mi 5S Plus, Mi 5X, Mi 5C, Mi 4, Mi 4C, Mi 4S, Mi 3, Mi Mix, Mi Mix 2, Mi Mix 2S, Mi Max, Mi Max 2, Mi Note 2, and Mi Note 3.
Redmi 6, Redmi 6A, Redmi S2, Redmi Note 5, Redmi Note 5 Pro, Redmi 5 Plus, Redmi 5, Redmi 5A (Redmi Y1 Lite), Redmi Note 5A (Redmi Y1), Redmi Note 5A Prime, Redmi Note 4 (4X), Redmi 4 (4A, 4X), and Redmi 3 (3S, 3 Prime, 3X, 3 Pro).
As for the date these devices will be upgraded to Android Oreo, Xiaomi has published a roadmap, details of which are on this page.