These are the Nova 4i and Nova 5e

While HarmonyOS is still unbeknownst to all in the west, the OS has a large user base in China, with reports claiming that as many as 50 million people use it. Currently, the OS is only available for Huawei devices. And, just like Android, this OS is based on a UNIX-like system.

Now the OS is making its way to older Huawei phones in China, specifically the Nova 4i and Nova 5e. To register, users have to go to the My Huawei app and select the early adopter upgrade program and then register for the public beta. In a sense, these steps are familiar to those who have pre-registered for Windows 11.

Huawei Nova 4i and Nova 5e HarmonyOS 2.0 compatible model numbers

Huawei stated in their HarmonyOS live stream that they want to cover as much as 100 Android devices including older models like the Mate 9 in China. It is still unknown whether HarmonyOS would also be available outside of China and due to their relations with the US and their allies, it's less possible right now.

Source: GizChina