Binary package “xlassie” in ubuntu xenial
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.