Android Settings > Notifications > {Chat Apps} (On)
Settings > Notifications > Notifications (ON), Show Preview (On)
Don't forget to enable notification in each room
Profile > Notification & Sounds > Notification previews (On)
Settings > Notifications > Conversation tones (On)
Settings > Notification Settings > Message Alerts (On), Display (Sender + Message)
Settings > Notifications and Sounds > Alert (On), Message Preview (On)