Install cairo-dock-mail-plug-in by entering the following commands in the terminal:
sudo apt update sudo apt install cairo-dock-mail-plug-in
Description:
Mail plug-in for Cairo-dock
A collection of official plug-ins and applets for cairo-dock. . This plug-in is very useful to warn you when you get new e-mails. This can check in any kind of mailbox (yahoo, gmail, etc).
Homepage: http://www.glx-dock.org/
Version: 3.4.1-2build1
Section: universe/x11