[ahaferburg]

What I don't get though is why these ancient mainframes need the latest version of the standard. I can't imagine the compiler writers for these OSs to be too eager implement any change at all. You said "technically possible", are you implying that nobody actually does? What are these OSs?

To me this seems like a weird take on accessibility. In order to accommodate that one OS that has some serious disabilities, everyone else has to suffer the consequences. Why not build a ramp for that one OS, and build stairs for everyone else?

[gpderetta]

IBM has multiple people in the standard committee and they care a lot for both backward compatibility and new standards. They alone were strongly opposed from removing trigraphs from the standard.

Still trigraphs were removed in the end; if there is enough support the committee is willing to break backward compatibility.