1. When you received the message on WhatsWhatsapp DO NOT OPEN IT, just head to settings and open or ON airplane mode.
2. Then open whatsapp and read your Message.
3. Now close the app fully (Apple users can double tap on the home button then swipe up on the WhatsApp window, while Android owners can tap the multitask button and swipe the app to the left
4. Then go back to airplane settings and switch it off.
With The Above your friends won’t know that you have read there message on whatsapp.