Verify your current kernel version:
uname -r
To update the Linux kernel, select a version from the following URL:
http://kernel.ubuntu.com/~kernel-ppa/mainline/
For example v4.14.13:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.14.13/
Download the files for the architecture that you require. i.e. amd64 generic:
linux-headers-4.14.13-041413_4.14.13-041413.201801101001_all.deb
linux-headers-4.14.13-041413-generic_4.14.13-041413.201801101001_amd64.deb
linux-image-4.14.13-041413-generic_4.14.13-041413.201801101001_amd64.deb
Once downloaded, issue the following command and reboot to update the kernel to the desired version:
sudo dpkg -i *.deb
Verify that the new kernel is being used:
uname -r