Please follow below mentioned steps to upgrade Ubuntu OS and kernels.
Step#1 Check current Ubuntu OS and Kernel version
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.1 LTS
Release: 16.04
Codename: xenial
Check current Ubuntu kernel version
$ uname -r
4.4.0-83-generic
Step#2 Update Ubuntu OS using following commands
$sudo apt-get update
$sudo apt-get dist-upgrade
This command will take some time to execute as it will download updated packages and will install it. Once this is completed, please execute following command to check the updated version of Ubuntu OS version
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.2 LTS
Release: 16.04
Codename: xenial
Ubuntu version is updated from 16.04.01 to 16.04.02. Now lets check current Ubuntu kernel version
$ uname -r
4.4.0-83-generic
If you have noticed, OS got updated but kernel did not. Ubuntu 16.04.2 installs a 4.8 kernel for new installations. For systems which are upgraded to 16.04.2 the current kernel series is maintained unchanged. If you have upgraded your system to 16.04.2 and want to have the new kernel, then you must opt in by explicitly installing the hardware enablement stack:
Step#3 Run following command to get Kernel updated
$ sudo apt-get install --install-recommends linux-generic-hwe-16.04 xserver-xorg-hwe-16.04
If you check Ubuntu Kernel status after completion of above install, you will get following output.
$ uname -r
4.4.0-83-generic
Confused, as kernel did not get updated ? Well, you need to shut down and restart OS and then run the same command.
$ uname -r
4.8.0-58-generic
6.04.x Ubuntu Kernel Support Schedule is as below
Please let me know if you run into any issues.