Install xlassie by entering the following commands in the terminal:
sudo apt update sudo apt install xlassie
Description:
Dockable mail notifier w/ message count & POP3/APOP/IMAP support
Enhanced pending mail notifier. Displays the number of waiting messages. Supports local mail spool and POP3/APOP3/IMAP mail servers. Can run a command when clicked upon. Uses plain xlib, so memory footprint is tiny. Can operate as plain app or WindowMaker/KDE dock applet.
Homepage: http://www.speakeasy.org/%7Exyzzy/xlassie/
Version: 1.8-21build1
Section: universe/x11