1) Uninstall and completely remove any previous WhatsApp version from your devices
2) Download the APK file by clicking here on your devices or on PC. If you have downloaded the APK file on your PC, you need to transfer it back to your device by connecting it to PC.
3) Just make sure that, you have done this already, open Settings, scroll down and tap on security —>Here, tick the box in front of Unknown Sources–>Accept the warning.
4) Install the file by tapping on it and following instructions
This should give you WhatsApp back on your devices. Do let us know whether it worked.
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