Enable proposed

Enable the -proposed pocket in order to test new packages before they are released to -updates.

On Ubuntu 24.04 LTS and newer

Enable -proposed with a new apt sources configuration:

cat << EOF | sudo tee /etc/apt/sources.list.d/proposed.sources
Types: deb
URIs: http://archive.ubuntu.com/ubuntu
Suites: $(. /etc/os-release && echo $VERSION_CODENAME)-proposed
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg
EOF
sudo apt update

To install a package from -proposed:

sudo apt install -t <series>-proposed <package>

On Ubuntu 22.04 LTS and older

Enable -proposed with a new apt sources configuration:

echo "deb http://archive.ubuntu.com/ubuntu/ $(. /etc/os-release && echo $VERSION_CODENAME)-proposed restricted main multiverse universe" | sudo tee /etc/apt/sources.list.d/proposed.list
sudo apt update

Prior to Ubuntu 24.04 LTS, it is recommended to add additional configuration to enable selective package upgrades from -proposed:

cat << EOF | sudo tee /etc/apt/preferences.d/proposed
Package: *
Pin: release a=$(. /etc/os-release && echo $VERSION_CODENAME)-proposed
Pin-Priority: 100
EOF

To install a package from -proposed:

sudo apt install -t <series>-proposed <package>