As it is quite well known, Canonical decided to drop support for the desktop it had created and adopted in 2010, called Unity. The current version, number 7, is quite stable, but it has not received substantial update in the last few years, when Canonical and its community were waiting for a major update, Unity 8, which would allow for convergence with phones and tablets. Since I have quite a good workflow with Unity, I decided to keep using it until it is is possible.
Installing Unity 7 in the new Ubuntu 18.04, which is going to be released at the end of April, is quite simple. It is only a command away:
sudo apt install ubuntu-unity-desktop
All files are still available and maintained in the universe repository. There is actually also a respin of Ubuntu with this desktop, and a community behind it, as shown in a community portal and a Trello bug-tracker.
My hope is that the UBports community, which has already an initial version of Unity 8 that runs on Ubuntu 18.04, will provide an update for this desktop to go into convergence with the phones and tablets using Ubuntu Touch.