Canonical has recently announced that Kernel fixes for Ubuntu 14.10, Ubuntu 14.04 and Ubuntu 12.04 have been implemented.
Once released, an Ubuntu system does not get any new features implemented, but kernel updates that include security fixes become available very often.
In order to get the latest kernel patches, you only need to perform a repository update and a regular system upgrade:
$ sudo apt-get update
$ sudo apt-get dist-upgrade
The upgrade instructions work on Ubuntu 14.10 Utopic Unicorn, Ubuntu 14.04 Trusty Tahr, Ubuntu 12.04 Precise Pangolin and derivatives: Linux Mint 17.1 Rebecca, Linux Mint 17 Qiana, Linux Mint 13 Maya, Pinguy OS 14.04, Elementary OS 0.3 Freya, Elementary OS 0.2 Luna, Deepin 2014, Peppermint Five, LXLE 14.04 and Linux Lite 2.