Ubuntu 14.04 Upgrade Kernel

Server

sudo apt-get install --install-recommends -y \
linux-generic-lts-xenial

Desktop

sudo apt-get install --install-recommends -y \
linux-generic-lts-xenial xserver-xorg-core-lts-xenial \
xserver-xorg-lts-xenial xserver-xorg-video-all-lts-xenial \
xserver-xorg-input-all-lts-xenial libwayland-egl1-mesa-lts-xenial 

Multi-Arch Desktop

sudo apt-get install --install-recommends -y \
linux-generic-lts-xenial xserver-xorg-core-lts-xenial \
xserver-xorg-lts-xenial xserver-xorg-video-all-lts-xenial \
xserver-xorg-input-all-lts-xenial \
libwayland-egl1-mesa-lts-xenial libgl1-mesa-glx-lts-xenial \
libgl1-mesa-glx-lts-xenial:i386 libglapi-mesa-lts-xenial:i386 

References

• Ubuntu Docs - LTSEnablementStack
• Ask Ubuntu - Can't Upgrade Ubuntu Enablement Stack