The secret to a long life
> "I still wonder if it is still being used..."
Many years ago the company that paid me to sit at a desk bought a proprietary system from an american company. It ran (IIRC) Solaris 2.6 and was the epitome of a "black box" solution. Data went in and something useful came out.
The machine was locked up tight. Nobody in the company had access to it. No-one knew the root password. It never received any software updates whatsoever and it kept running.
It seems to me that provided the o/s and the apps are stable and that adequate security is implemented, there is never any need to perform updates - or introduce new bugs as the skeptic might describe the process.
Is it still running today? Doubtful, since external environments change and boxen that do not change with them become obsolete. However that little box was the "perfect" computer. it never needed maintenance. it never crashed. It just quietly got on with its job.
I suspect that if it had been allowed to, it would continue running indefinitely. Much like that Linux box that gets stuck on boot-up with "a start job is running ... no limit" report on the (text) console. That is, if the user knows how to get to the text console.