mail-notification software package provides mail notification in system tray, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install mail-notification
mail-notification is installed in your system.
Make ensure the mail-notification package were installed using the commands given below,
$ sudo dpkg-query -l | grep mail-notification *
You will get with mail-notification package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | GNOME |
| Package | mail-notification |
| Version | 5.4.dfsg.1-9 |
| Description | mail notification in system tray |
| Sub Section | GNOME |