+ Need ROOT.
+ Set timing and Screen-off timeout properly in setting.
+ Select Camera Button.
+ Grant Super User permission when asked (Make it permanent and disable notification in super user for this app for better usage. Don't worry).
+ Put red box in tick mark area of message you want to monitor (You can Pan, Zoom the image, You can move red box).
+ Press OK.
+ Make sure no other notification happens on the screen. The screen should be identical to the one when you presses OK button.
+ To avoid other whatsapp messages disturbing, archive them.
+ When message is updated (Delivered / Read), you will get notification.
+++ Please Understand, this app works only when the part of screen by red box selection doesn't change for any reason. except whatsapp message update.
+++ First time because of super user permission dialog, the picture mayn't be correct.
+++ In case of interruption, please repeat the process to avoid wrong notification.
+++ If you want support for your language, mail me
If you like this free, no adv app, please share it and rate it 5 star.
Before comment negatively / rate low, please try to contact me. If possible i will try to update the app.
Screenshots