If a challenge gives a set of languages to choose from, how freely can I choose a version?
Concrete example: I found a solution for a challenge in JavaScript. The challenge just lists a number of languages that are valid for that challenge, and JavaScript is one of them.
But my solution is kind of limited.
It is only working on JavaScript used in Mozilla Firefox and even they dropped support of that feature for version 12 and later. So on the one hand I agree it is nothing one really would use in any productive code. But on the other hand, technically seen, that's what JavaScript was about that time.
So would it satisfy the requirement as being JavaScript? And if not, where is the border between valid and too restricted?