Battery saving - WhatsApp My WhatsApp messages have been delayed and I believe it is because of the power saving being on. I want to keep it on because my battery drains, but WhatsApp does not seem to be in the unmonitored apps list. Is this normal or how do I resolve? I'm on a Galaxy S6
Go to the Settings app,
Go to Battery,
Tap the ... button in the upper-right corner,
Tap Battery Optimization,
Tap the Not Optimized drop-down and select All Apps.


Disabling battery optimization for a specific app


Locate the app you want to disable battery optimization for.
Tap the app in question.
From the popup, tap Don't optimize.
Tap DONE.


Enabling battery optimization for a specific app


Locate the app you want to enable battery optimization for.
Tap the app in question.
From the popup, tap Optimize.
Tap DONE.


Source: TechRepublic