Canonical has announced the availability of Ubuntu 18.04.4 LTS. The new update is a point release which rolls all of the latest updates into a single disc image saving you time when you do a clean install as you have fewer updates to install. Also, this update includes hardware enablement stacks which adds support for newer hardware.
The new point release is available for Ubuntu on Desktop, Server, and the Cloud as well as other flavours of Ubuntu with long-term support including Kubuntu, Ubuntu Budgie, Ubuntu MATE, Lubuntu, Ubuntu Kylin, and Xubuntu. Detailed release notes for each of these flavours can be found on the Ubuntu Wiki.
Each Ubuntu LTS release ships with five years of maintenance updates, this means that Ubuntu 16.04 LTS will reach end-of-life around April or May 2021. If you’re still using this older release, Canonical will offer you an automatic upgrade to 18.04.4 via the Update Manager, you can find detailed instructions for upgrading here.
If you’re already running Ubuntu 18.04 LTS and have all of the latest updates installed then you’re effectively on Ubuntu 18.04.4 and you do not need to do anything. Additionally, if you have Ubuntu 18.04 installation media, there is no need to throw this away as you only need to apply post-installation updates to be running the latest software.