At the boot: prompt for the cd, type linux askmethod
and select from the list.
If local CDROM
isn't in the list, you have a custom install cd.
If that's the case, you'll need to download a newer version, which is going to be a far better option technically and securitywise..
There are servers with the distro files and the updates (at least until they were retired), but downloading those in preference to downloading a modern distro seems an interesting use of your time..