You are not the only person running an outdated Linux...far from it
I still need to know which version of Linux Mint you have. It is possible you have an outdated version .....quite possibly Linux Mint 17.1 ... This version DID NOT include Libre Office.
Back in January, you told us you were using Libre Office 6.4.7.2, and so I was able to establish that you were likely using Linux Mint 20.2 'Uma' or thereabouts, and advised some helpers to that effect.
Good luck getting the info out of him.