Install gnubiff by entering the following commands in the terminal:
sudo apt update sudo apt install gnubiff
Description:
mail notification program for GNOME (and others)
gnubiff checks for mail within a file, a qmail or MH style dir, or an IMAP4 or POP3 or APOP server. It can display headers (number, sender, subject, and date) when new mail has arrived. . While gnubiff is implemented as a GNOME panel applet, it also runs as an independent icon on the desktop in other environments.
Homepage: http://gnubiff.sourceforge.net/
Version: 2.2.17-1build1
Section: universe/mail