We have the national branches of several well-known Fortune 500 companies as customers, and they rely on our Delphi-based software for their daily operation. As in, if our software stops they can't do their primary thing.

Our software is under active development, but we're transitioning away from Delphi. Mainly due to the difficulty finding developers who want to work with it, and C# and .Net now is a much more compelling platform than it was 20 years ago.

Doesn't help that desktop-oriented applications going the way of the dodo, effectively neutering the main selling point of Delphi: its RAD capability.

There are a lot of companies using Delphi where I live (Brazil), food distribution, point of sale, HR, construction, etc. In fact, the first real job I had was developing software with Delphi. I know half a dozen people from the industry who have been working with it for more than 10 years. It’s not a flashy gig, but it’s stable.

A lot of industrial automation around the world, but especially in Russia, likely run on Delphi.

Of course we're talking about stuff like rail yard management, not ticket booking. That used to be mainframe based, but is likely Enterprise Java for the last two decades or so.