Just after Ubuntu new release also derivative distributions arrived as well. I so went through the upgrade process of the Xubuntu installation on my (old) desktop computer. I've been informed of the availability of the new release with the, almost daily, software update request. I then selected the “upgrade” button and let the whole process start.
the upgrade proceeded slowly but quite smooth, it showed some error in the process but it doesn't seem to have influenced the final result.
Here is my upgraded system
As I often say, about upgrading older computers, “No news good news”, the whole system continue working as good as before. Some little improvements are visible from the beginning like the better integration with Thunderbird mail client, than has now become the Ubuntu's default one. Some odd behaviour may arise if you, like me, use Gnome applications inside the XFCE environment. Nautilus, for example, opens a background window that you can't remove unless you kill it by console.
I suppose this window is in some way required to render the new menus on the top of the screen. You can, of course, go back using the good XFCE default file manager Thunar or live with this odd side effect. I only hope that windows manager developers will keep an eye on little compatibility problems like this while searching new and cool ways to let us interact with the computer.