What if an interpreter update invalidates an existing answer?

Question

I noticed earlier today that the Befunge interpreter on TIO no longer functioned in quite the same way as the old version (I guess this was caused by the nexus update). As a result, one of my old answers that relied on undefined behaviour that was specific to the TIO implementation is now no longer valid. I was quite happy to just delete that answer, since it only had one upvote anyway, but I'd like to know what the recommended practice is for these situations in general.

I know my particular case is probably not that common, but I suspect a lot of the golfing languages used on this site are evolving in ways that might not always be backwards compatible and could occasionally invalidate old answers. If that happens, are people expected to update those answers to be compatible with the latest version of the interpreter? Do they just leave their answer broken? Or should they delete the answer if they can't or don't want to fix it?

Answer 1

The old interpreter conceptually still exists, even if it's no longer accessible

We require that the interpreter predates the question. We don't require that the interpreter still be available at the time the question is asked (except for occasional cops-and-robbers questions where the ability of robbers to run the programs is important). Presumably in this case it'd be possible to track down the specific version of the interpreter that was used, and run it locally; TIO must have got it from somewhere.

Or to put it another way, languages are defined by their implementation on PPCG, so a new version of the implementation conceptually creates a new language, and doesn't cause the old language to cease to exist.

Thus, the answer doesn't become invalid simply because the interpreter has fallen off the Internet (and in this case, it probably hasn't!); it was there at one point.