This feature is available on IOS as well as android version. Now there is no maximum limit.
How to enable?
1) You can go to chat you want to mute.
2) Click on three buttons on right corner.
3) Select “Mute notification.”
4) Select the time limit to mute the chat.
A) 8 hrs. B) 1 week C) Always.
So now you can mute the chat which are annoying to you. So enjoy this new Whatsapp feature.