Script to update between releases is finally ready, and with that I am taking this out of pre-release!
To get the update script use the following commands:
wget https://raw.githubusercontent.com/TheRemote/Ubuntu-Server-raspi4-unofficial/master/Updater.sh
chmod +x Updater.sh
sudo ./Updater.sh
You can update from any pre-release release version. Please make a backup first!
The updater is located at /home/Updater.sh on v15 and up (to run type sudo bash /home/Updater.sh)