As you can see, there are unread in app notifications still there even the chats are muted.
I have a rooted device running Lineage OS 14.1 (Motorola's Moto G4 Plus).
Please don't mark this answer as duplicate, as the other thread's answers are not working for me.
ShutApp is not working for me (Android 7.1.1). Someone on ShutApp's website pointed that it doesn't work on Marshmallow too.
This is ShutApp's link:-