$ sudo apt install gnupg dirmngr ca-certificates curl --no-install-recommends
$ curl -s https://dl.jami.net/public-key.gpg | sudo tee /usr/share/keyrings/jami-archive-keyring.gpg > /dev/null
$ sudo sh -c "echo 'deb [signed-by=/usr/share/keyrings/jami-archive-keyring.gpg] https://dl.jami.net/nightly/ubuntu_20.04/ ring main' > /etc/apt/sources.list.d/jami.list""
$ sudo apt-get update && sudo apt-get install jami