as long as I am not hindering the network I will leave it on 0.18 until such time as I can figure out how to install a new version, I don't keep any bitcoin in the wallet - thank you
Most of my peers are running 0.16 which is an even older version, so relative to the rest of the nodes on he network, yours is running a fairly recent version.
If there's execution permission problem, enable execution from ubuntu file manager or run this command
chmod +x bitcoin-qt
Linux binaries have the executable bit turned on by default, when you compress a file into a tarball, it stores the permission bits inside as well. It would be different if you were unzipping a .zip file; no permissions are stored in there, so you need to run chmod +x before you can run it.