iOS:
iPhone - iOS 12 or later
iPad tablets not currently supported.
Android:
Phones - Android 7.0 or later
Android tablets not currently supported.
Huawei & Xiaomi:
Not compatible.
On May 16, 2019, the US government placed Huawei/Xioami on its Entity List. This government action prohibits all US companies, from collaborating with Huawei. This means that also the Apple-App-Store/Google-App-Store is prohibited from working with Huawei/Xiaomi.