Because there are other upgrades in systems that can affect your server-system upgrades, affecting its compatibility as a server.
The question is this: is this used as a PC or a server? If a server, get appropriate server software that is current and rebuild the system as a server as opposed to a PC box.
It’s primarily what you might call a one-way file server. Other than a basic PHP/MySQL for password verification (to allow access to downloadable files), the machine runs Apache for the HTTP interface, and that’s it.
It’s a standalone PC that’s outside the firewall of my internal LAN.
The only directory accessible without going through the PHP/MySQL password is protected using a .htaccess file