echo 'deb http://archive.ubuntu.com/ubuntu/ focal-proposed main restricted' >> /etc/apt/sources.list apt update apt install libx11-6
verify with 'apt-cache policy libx11-6' that you have the correct version (from proposed), and run your tests.
echo 'deb http:// archive. ubuntu. com/ubuntu/ focal-proposed main restricted' >> /etc/apt/ sources. list
apt update
apt install libx11-6
verify with 'apt-cache policy libx11-6' that you have the correct version (from proposed), and run your tests.