For some reason my NotificationCompat.Builder will not accept 2nd argument and I have no idea how to fix it. I saw some other answers but mostly the problem was
Please make sure that you are including the correct version of the NotificationCompat library: import android.support.v4.app.NotificationCompat;. Here is the official guide on Notification Channels, which are a new feature as of Android O: https://developer.android.com/training/notify-user/channels.