The hold mark could be left over when an upgrade operation fails midway. If there are no apt operations pending. You can remove the mark safely. After this you can run upgrades manually.
What really gave me a hard time was finding out the FBX administrator doesn’t have the privileges for performing tasks with apt.
I know the commands “sudo” and “su” but it took me quite a while searching the docs to realize I had to combine these two in order to become root. Very puzzling for me, I still don’t grasp the underlying concepts.
But the documentation helped me find my way, so thanks for this as well!
Michael
Edit: How can I mark this topic as solved? I can’t seem to find this option.