There are lot of Android applications and games APK on the Internet. Or the one that you backup from existing apps or games. Yes, they are in APK file format. And normally you can’t install them as Google blocked it by default because the safest way to get Android applications and games is through Google Play Store. Anyway, you still can install 3rd party APK on Redmi 2 through File Explorer.
How to install 3rd party apps / games APK on Xiaomi Redmi 2?
It is very simple to do so. Just copy the APK that you want to install to Redmi 2. Or download from Internet directly to your smartphone. Then open File Explorer. Select APKs. It will list down all the APK on your device. Then select the one that prefer to install. Then allow and install it. That’s all.
How to re-enable security prompt back? Go to Settings. Select Privacy then Device administration. Disable Unknown sources ~ Allow installation of apps from unknown sources. Get it?