I believe those are closed systems not connected to the internet. It still would be better to upgrade them (for easier access to spare parts, knowledge, etc).

I believe those are closed systems not connected to the internet. It still would be better to upgrade them (for easier access to spare parts, knowledge, etc). Otherwise they end up like this French airport which was shut down just few weeks ago because their Windows 3.1 failed. https://news.ycombinator.com/item?id=10559687 https://news.ycombinator.com/item?id=10559687