What is the correct way to deal with obsolete answers?

Question

Sometimes old answers were correct at the time they were written, but the march of technology has made them obsolete.

For example, the command-line video encoding tool ffmpeg used to have a 'vhooks' function, but that has been replaced by an entirely new syntax, making this answer incorrect for all recent versions of the program. However, when I flagged the answer as such, my flag was rejected on the grounds that

flags should not be used to indicate technical inaccuracies, or an altogether wrong answer

So my question is: what is the correct response to this kind of obsolete answers? Downvote & leave a comment? Edit the question to correct it (would seem to be little too drastic a change for an edit)? Something else?

Answer 1

As a user, comment (as of goobahapp v.2, the -pulverise option has been replaced with the -atomise option), edit if its minor changes, post a new answer highlighting this if not.

I'm personally not a fan of a downvote here, commenting on why is necessary in this case, and serves the same purposes, and it isn't clear if you 'just' downvote. (Downvote and commenting is I guess fine. Commenting is almost compulsory here).

I'd want the older answer kept, since not everyone uses the latest and greatest versions of things (what if you were running debian stable or oldstable, or RHEL, where packages are selected for stability no matter what the age). I have a dissenting view and still consider these useful as long as its clear that, well, it depends on the version.

Answer 2

Note that moderators should not be judges of what's correct or not. You may be right in that the option is deprecated (or missing) and the solution in the post doesn't work anymore, but that's why you can leave down votes. If moderators had to do all the dirty work of trying to prove solutions correct, we'd have no time to spend on the issues that really deserve immediate attention.

The ideal solution in such a case, of course, is to edit and correct the answer if you can.

Since our editing guidelines say that you should keep edits substantial, but not radically change the meaning of a post, we welcome any edits that correct obvious mistakes, but don't rewrite the entire answer if possible. If you suggest an edit for improvement and it gets rejected, try and see if the OP is still active so you can ask them to fix their post with your help.

You could also come to Meta when you spot a bunch of outdated and wrong answers.

If editing is not possible or would require a major rewrite of the post, you should rather downvote and comment. Explain what exactly is wrong with the post and how to possibly fix it.

Finally, you can always post a new, correct answer—just like you did in the example you gave. Unless the existing posts already accumulated tons of votes, or the wrong answer "sticks" at the top because it was accepted, this will make your post float to the top eventually once enough people voted for it.

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Update in light of comments about rep loss and punishment for something that was correct at the time posted:

In the context of this Meta question, we're talking about a tool that you probably constantly update. A tool whose developers fix thousands of bugs in a year, constantly add features and remove others as they go. Most visitors who search for solutions and come to Super User will therefore see posts that simply don't work. These posts are not useful anymore.

Putting a disclaimer into these answers is possible, but what greater goal does this serve? It's bad enough that many resources on the web become outdated and nobody cares to fix them, but we have plenty of options to correct that.

If your answer becomes obsolete, why would you want to have it around in the first place? I'd be happy to be able to fix old answers of mine if they happened to become outdated due to removed features, etc. But if I can't fix them, I'll delete them, so as not to put wrong information out there, and give way for newer and better answers.

Answer 3

Perhaps there should be a lock on the question resulting in something such as:

It would prevent any addition, potentially wrong/confusing answers from being posted and would still keep the contributors' reputation intact. Further, it would prevent anyone from needing to edit the actual question/answer, which more or less wouldn't be read anyway.

The unquestionable fact is that some questions are no longer up to date or otherwise relevant in today's information base. It would be similar to a historical lock but would have the advantage of letting users know that it was closed specifically for the fact that it contains information that could be completely wrong if applied to a new version, instead of marking the question as old.

Note that moderators should not be judges of what's correct or not.

In this case, put it back in the hands of the general user, with another vote option, or an addendum to the "off topic" vote option as being "obsolete".