s8 and nougat heads up notifications

I found a solution, first go to settings 》notifications 》 from all apps choose the application you want to hide the notifications from ( whatsapp for example) and inside the (app notification) choose the option show silently. This will not allow the heads up preview to show but it will allow the icon to apear in the upper corner as u receive a message unfortunately you will miss the sound/ and vibration as well. But i downloaded a third party application ( good vibrations ) and choose this application to sound/vibrate when i receive a WhatsApp message. And problem is solved...yahuuuu... i hope it works for you if it does i appreciate your support in folowing me on Instagram ( mayyoub )

Does this solution disable the LED? Because I did all what you said and I don't get the LED notification :(
 
OMG...like u all..i was also too much annoyed with this whatsapp message preview on screen from almost 6 months...i also tried many things bt failed...yesterday i read all these comments..tried some of them..bt it was not exactly what i wanted..so a while ago i was searching by myself and guess what i found the solution..m soo happy guys..i was too much tensed abt this..well let me help u too..
Go to Setting>Apps>whatsapp
Then click on notifications
It wil further open
Under Chats category,u wil see Group Notifications and Message notifications
Click on Message notifications..it wil further open
U wil see "Importance" written under the On button..Click on "Importance"..there wil be options like Urgent,High,medium,low
Select "High"
This is it...u only have to uncheck Urgent and Check High...even u wil also see that under High,it wil be written that there wil be only sound notification..
Check this and try it...
Its too much easy..and m so relieved now..may ur problem get fixed too
And yes u should turn off the pop up notification from whatsapp also..cz may be it wil cause a problem..bt i had made it off already