Changing sound and vibration for Notification Channel on Oreo 8.1

Question

Officially sound and vibration for a Notification Channel are "Only modifiable before the channel is submitted to NotificationManager.createNotificationChannel(NotificationChannel)."

But I saw now that when a go to Whatsapp settings and change the sound or vibration, those changes appear in the setting for the respective channel (Private or Group).

How can I do that? (I'm using android 8.1)

Answer 1

Whatsapp doesn't edit the channel, simply for any change you make they delete the channel and create a new one with the same name (with different id). I perceived now that every time you make changes the 'Deleted categories' count goes up.