In my opinion, the code in the launcher should be
if ! $docker_path info 2> /dev/null | egrep -q '^Storage Driver: (aufs|btrfs|zfs|overlay|overlay2)$'; then
if ! $docker_path info 2> /dev/null | egrep -q '^Storage Driver: (aufs|btrfs|zfs|overlay)$'; then
There is no reason for this message if using overlay2.
Your Docker installation is not using a supported storage driver. If we were to proceed you may have a broken install. aufs is the recommended storage driver, although zfs/btrfs and overlay may work as well. Other storage drivers are known to be problematic. You can tell what filesystem you are using by running "docker info" and looking at the 'Storage Driver' line.