When this was last asked four years ago (How to deal with obsolete answers?) the gist of the responses was, "Trust the voting system: obsolete answers will be downvoted, and even if there is a marked answer people will come along and update it or provide new answers with more current information."
This is great in theory, but I have seen no evidence that this works in practice, probably because:
- It feels mean-spirited to downvote what was once a good answer just because it's outdated.
- If a question has a lot of highly-voted old answers any new, more current, answer is likely to languish at the bottom.
- There seems to be little incentive to provide another answer to an old question with an accepted answer: unless the asker is still very active your updated answer is unlikely to ever be marked as accepted, and readers are unlikely to browse down the list for more current answers when an accepted and highly-voted answer is shown first.
I know none of these should be the case, but they seem to be the reality and I believe the community should take them into account when flagging a question as duplicate or already-answered.
For example, I recently asked this question for current technology and it was marked as "already answered" ... three years ago! I protested and was told the correct course of action to get an updated response would be to up-vote the old question, comment on it, or post a bounty on the old question (though I lack rep for that).
Again, I like the theory, but can we offer a more practical course of action in cases where the question is similar but the times — and answers — are likely not?