Ubuntu 18.04 aka Bionic Beaver was released on 26 April this year. This is a LTS (Long Term Support) Release. It was one of the most awaited release version.
In this tutorial we will see how to upgrade ubuntu 16.04 (Xenial Xerus) to 18.04
1. Search for Software and updates in the dash, after that select the updates tab and select For long term support version from the Notify me about a new Ubuntu version option.
2. Open up the terminal (ctrl+alt+t)
update and upgrade software packages.
sudo apt update sudo apt upgrade
3. enter the following command in the terminal itself.
this will open up the upgrade windows, asking if you want to upgrade to 18.04, click on upgrade and follow the onscreen instructions.