LTS HWE Stacks
The Ubuntu LTS enablement (also called HWE or Hardware Enablement) stacks provide newer kernel and X support for existing Ubuntu LTS releases. These enablement stacks can be installed manually but are also available when installing with Ubuntu LTS point release media. These newer enablement stacks are meant for desktop and server and even recommended for cloud or virtual images.
For more information, please refer to https://wiki.ubuntu.com/Kernel/LTSEnablementStack