As you may know, Geary is a lightweight email client, written in Vala, built for the Gnome desktop. It is also the default mail client on Elementary OS 0.2 Luna.

The latest version available is Geary 0.10.0, which has been recently released, coming with the below changes:
- Undo Archive/Trash/Move of email
- New split headerbar layout with UI, composer improvements
- Preference to switch between 2-column and 3-column layout
- Support multiple (“alternate”) email addresses per account
- New shortcut keys to navigate next/previous conversation
- Fix displaying inline images referenced by Content-ID
- Numerous bug fixes, optimizations, improvements
- Updated translations
Installation instructions:
Up to date packages are available via some third party PPA, so installing the software on Ubuntu and derivative systems is easy. Add the PPA to your system, update the local repository index and install the geary package:
$ sudo add-apt-repository ppa:yorba/ppa
$ sudo apt-get update
$ sudo apt-get install geary
Optional, to remove geary, do:
$ sudo apt-get remove geary
The installation instructions should work on Ubuntu 15.04 Vivid Vervet, Ubuntu 14.04 Trusty Tahr and derivative systems like Linux Mint 17.2 Rafaela, Linux Mint 17.1 Rebecca, Linux Miny 17 Qiana, Pinguy OS 14.04, Elementary OS 0.3 Freya, Deepin 2014, Peppermint 6, Peppermint 5, LXLE 14.04 and Linux Lite 2.