Note: these steps are only for Devuan stable (excalibur).
cat << EOF | sudo tee -a /etc/apt/sources.list
deb http://deb.devuan.org/merged excalibur-backports main
deb-src http://deb.devuan.org/merged excalibur-backports main
EOF
sudo apt update && sudo apt install bitcoin-knots/excalibur-backports datum-gateway/excalibur-backports
You can choose between two configuration mode:
sudo dpkg-reconfigure -pmedium bitcoin-knots datum-gateway
sudo dpkg-reconfigure -plow bitcoin-knots datum-gateway