Canonical has released the latest point release (or service pack in Microsoft language) for Ubuntu. Ubuntu 16.04.3 rolls all the updates the operating system has received into the ISO to save users having to re-install all the available updates. In addition, 16.04.3 ships with a new Hardware Enablement (HWE) stack which includes an updated kernel.
The HWE stack in this release includes the Linux 4.10 kernel and the Mesa 17.0 graphics stack; both of which are available in the 17.04 Ubuntu release. HWE kernels are only supported until the next HWE stack is made available, therefore it is important to keep your system updated in order to continue to get security updates for kernels.
For users already running Ubuntu 16.04, updating to the new point release is simple, just install the updates offered by the Update Manager. Those of you who install 16.04.2 will automatically receive the HWE stack, however, if you install 16.04 or 16.04.1 then you'll not receive the new HWE stack because they shipped with the original GA kernel which is supported for the entire lifecycle of the release.
If you fall into the latter category but want the new HWE stack, then you can install it with a single command (server users should omit the xorg package): sudo apt install –install-recommends linux-generic-hwe-16.04 xserver-xorg-hwe-16.04
The new ISOs are available for download right now over at Ubuntu.com and are supported until 2021.