As of our 1.2 release, ARDK officially supports Unity 2020.3 LTS, and Unity 2019.4 LTS. Starting with our next release 1.3 (coming soon) ARDK will no longer officially support Unity 2019.4—Unity has announced that 2019.4 is now legacy LTS and will reach the end of its support in spring 2022. More information here: Unity QA - LTS Releases - Unity