You cannot run the latest Netflix app (version 8.x or 9.x) on Android 7.1.2. However, – specifically Netflix APK versions between 6.26.1 and 7.99.x – can still function, provided your device meets basic Widevine L3 requirements.
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on how to safely sideload an APK using a USB drive on your specific TV box? Older versions of Netflix (Android TV) (Android) | Uptodown
: Widely considered the most stable "legacy" version for older uncertified boxes.