See also: LTSP PPA documentation.
LTSP releases are normally published in the LTSP proposed PPA and after a few days, if noone complains about regressions, they are copied to the LTSP PPA. That means that most LTSP administrators should have the proposed PPA in some test installation or in their personal computers etc, to be able to test new releases and file issues before they reach their production setups.
To install the repository, run the following commands as root:
add-apt-repository ppa:ltsp/proposed apt update
wget https://ltsp.org/misc/ltsp-ubuntu-proposed-focal.list -O /etc/apt/sources.list.d/ltsp-ubuntu-proposed-focal.list wget https://ltsp.org/misc/ltsp_ubuntu_ppa.gpg -O /etc/apt/trusted.gpg.d/ltsp_ubuntu_ppa.gpg apt update