This post has been closed (why?): https://forums.garmin.com/sports-fitness/cycling/f/edge-130/148492/whatsapp-notifications
but EDGE 130 has not yet true "smart" notifications (like whatsapp), only "base" notifications (phone call & SMS).
Apparently there are no technical reasons (neither hardware nor software). A device like Vivoactive 3 smartwatch (same price range) he always had true smart notifications...
Garmin, We're waiting confident!