From 2019 to 2024, versions 1 to 4.3 (4.5 TV) of the operating system were built by integrating the Android Open Source Project (AOSP) with OpenHarmony, allowing it to support both HarmonyOS and Android apps.[11] The current iteration of HarmonyOS became known as HarmonyOS NEXT (later it was renamed HarmonyOS 5 in launched of Pura X). HarmonyOS NEXT was announced on August 4, 2023, and officially launched on October 22, 2024.[12] It also replaced the OpenHarmony multi-kernel system with its own HongMeng Kernel at its core and removed all Android code. Since version 5, HarmonyOS only supports apps in its native “App” format.[13][14]

HarmonyOS 5.x+ both discards the common Unix-like Linux kernel and replaces the previous multiple-kernel, kernel agnostic system from OpenHarmony with its own bespoke HarmonyOS microkernel as a single framework.

- https://en.wikipedia.org/wiki/HarmonyOS