Just some quick notes to upgrade Nvidia driver from 390 to 396 on Ubuntu 18.04. By default Ubuntu 18.04 only has Nvidia driver 390.

# add ubuntu official ppa for nvidia
# all commands below run as root
add-apt-repository ppa:graphics-drivers/ppa
apt update
# install 396 files
apt install nvidia-dkms-396 nvidia-driver-396 nvidia-compute-utils-396 libnvidia-compute-396
# reboot at the end.

After reboot, the new driver can be verified by:

nvidia-smi 
 +-----------------------------------------------------------------------------+
 | NVIDIA-SMI 396.54                 Driver Version: 396.54                    |
 |-------------------------------+----------------------+----------------------+
 | GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
 | Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
 |===============================+======================+======================|
 |   0  GeForce GTX 1070    Off  | 00000000:01:00.0 Off |                  N/A |
 | 44%   67C    P2   150W / 230W |   3211MiB /  8117MiB |    100%      Default |
 +-------------------------------+----------------------+----------------------+

🙂