Mastodawn

A notification badge is often a red dot that shows a digit. That digit is the unread-message count.

The digit in the badge must match the unread-message count!

Lately, I've seen a badge promising 1 or 2 messages in the Google Play Store, a telco app, and a banking app when there were no unread messages.

Incorrect system-status info is a defect. It'll train users to pay less attention to the badge.