Operating Systems and Older Phones

I’ve been trying my bound on an iPhone 6 running iOS 12.5.7 - the app store asks me to download an older version of the app. When running on this phone, correct answers in multiple choice quizzes are often marked incorrect. A friend has also said this happed on an older Android phone.

Can anyone give me the lowest OS numbers on both devices that the app will run correctly on please?

Dear gyheritage
The current version (2.16.7) is supported on iOS 14 and Android 10 and better.
Kind regards

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