By the nature of tabletop games, rule books will come out that provide RAW answers to questions that have been asked before, were answered, and that answer was accepted; however, due to the new rule book that accepted answer is no longer correct.
This question's not an ideal example, but close enough for these purposes.
Is the burden solely on the original querent to remove and reassign the checkmark? Should we flag the question for moderator intervention? Or do nothing?
Alternately, is it appropriate to edit the accepted answer to indicate that it was provided prior to the release of material that contradicts or refines the answer?