Latest Kernel for ubuntu 14.04.4
Solution 1:
You do not have to upgrade your kernel. Kernel 3.16 still gets security and bug fixing updates.
But you CAN upgrade the kernel to 3.19 by
sudo apt-get install linux-generic-lts-vivid
or to 4.2 by
sudo apt-get install linux-generic-lts-wily
It is even possible to upgrade to kernel 4.4, but that may cause issues with DKMS modules
sudo apt-get install linux-generic-lts-xenial