Should I remove my answer which has been invalidated by an edit to the question?

Question

For the question Should I report a PhD student’s incompetence to their supervisor? I gave an answer based on an assumption that the OP and a supervisor were based at the same institution - information which was not originally apparent. Since then, OP has clarified that my assumption was incorrect, and this invalidates my answer.

Should I now remove my (substantially upvoted) answer which does not address OP's exact situation? Or should I leave it to stand on the basis that it may be helpful to others in similar but not identical situations? In any case I will add a note to indicate my incorrect assumption.

Answer 1

I don't think you should delete your answer. Even though it doesn't address the OP's situation exactly, it's a good answer that can be useful to others experiencing a similar situation within their institution. The disclaimer you added should be enough to warn the reader.

Answer 2

The purpose of Stack Exchange is not merely to provide immediate answers to people with immediate questions, but also to allow people who have similar questions in future to benefit from the answers that have already been written. If the Question is one that would likely be found by people seeking the answer for the question you answered, your answer would be of benefit to those people whether or not it is of benefit to the person who asked the original. If the Question has changed so that it would no longer be found by such people, it may be worthwhile to post the question which you had answered as a new Question, copy your answer to that, and remove it from the original where it no longer applies. Moderators may have tools to migrate answers without having to delete and re-post, but I don't know how that would be done.