wget https://updates.duplicati.com/beta/duplicati_2.0.6.3-1_all.deb
sudo apt install ./duplicati_2.0.6.3-1_all.deb
sudo apt install mono-complete -y
sudo systemctl enable duplicati
sudo systemctl start duplicati
sudo systemctl status duplicati
open http://localhost:8200 in browser

Enable Remote WebUI (from another machine on network)
sudo nano /etc/defauts/duplicati
DAEMON_OPTS="--webservice-interface=any --webservice-port=8200"

Fix EVP_MD_size assembly: type: member:(null) DismissShow
wget http://nz2.archive.ubuntu.com/ubuntu/pool/main/o/openssl/libssl1.1_1.1.1f-1ubuntu2.16_amd64.deb
dpkg -i libssl1.1_1.1.1f-1ubuntu2.16_amd64.deb