If it ain't broke, don't fix it.
Many healthcare systems are a COBOL-dialect all the way at the bottom. Some of these had PHP layers shimmed in, when the web became a thing.
I've seen php scripts that shell out to .bat's, that interface with the COBOL engine. It's a mad world.
For context, a large amount of healthtech software was written in the 80s (kind of like fintech, the difference is that there's no competitive advantage to having better technology in health).
It's a minor miracle that anything works at all.