Flatpak

https://flathub.org

Config dir: ~/.var/app/

Install flatpak core

https://flatpak.org/setup/Ubuntu

sudo apt install flatpak
sudo flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
flatpak update

Usage

flatpak search nagstamon
flatpak info de.ifw_dresden.nagstamon
sudo flatpak install de.ifw_dresden.nagstamon

Full upgrade

flatpak update
flatpak update --appstream
flatpak repair --user
sudo flatpak repair --system
flatpak update
flatpak uninstall --unused