Configure which WhatsApp message events reach your webhook. events is the COMPLETE subscription set for this channel: omit an event to unsubscribe it. url is optional and shared with the SMS/VOICE webhook, so sending it changes the delivery URL for every channel; omit it to keep the one already configured. It is required only when no URL has been configured yet. This endpoint never removes the webhook: use PUT /v2/webhooks with no url for that. Your SMS/VOICE subscriptions are left untouched.