The Mi Fit notification sending service for the Mi Smart Band 4 bracelet resends all WhatsApp notifications, including group notifications ("You have 2 messages") that are not useful when they are forwarded to the bracelet. This app relays messages, without group notifications.
Remember to indicate in Mi Fit that * yes * you want to receive "Application Alerts" from this app, and * no * you want to receive them from WhatsApp, so you don't get duplicate alerts.