Little markers on app icons to show unread alerts, similar to iOS.
If you are currently on an older version of ColorOS 3.2, you can check for the final official stability patches: Open the app. Go to Software Updates . oppo f5 android 80 oreo update
A common concern with older mid-range phones (Helio P23 processor, 4GB RAM) is that a major OS update might cripple the device. Here is the honest verdict on the Oreo update: Little markers on app icons to show unread