Follow mostly the instructions available here:

  1. Install all available updates
sudo apt update && sudo apt dist-upgrade
  1. Download and install the latest development version
sudo do-release-upgrade -d
  1. Verify which version of Xubuntu I am using:
lsb_release -a

Troubleshooting expected

Losing xfce desktop

Followed advice from this resource

  1. While not logged in, go back to the first tty (Ctrl+Alt+F1).
  2. Execute:
cd $HOME/.cache
rm -rf sessions
  1. Go back to the gui tty (Ctrl+Alt+F7) and log in normally again.
  2. Update via terminal everything, inspired from sudo apt-get update
sudo apt-get update
sudo apt update
sudo apt-get upgrade
sudo apt upgrade
sudo shutdown -r now