Answers with broken links to software that is no longer available

Question

Six years ago I asked a question for recommendations for Firefox extensions: Firefox extension to copy the title and URL of the page to the clipboard. Since then, Firefox completely changed the way that extensions work. Most answers recommend extensions that are:

1. No longer available (the pages on the Firefox site for them are 404 Not Found.)
2. Don't work with Firefox anymore even if you found an alternate source to download.

I recently received an up-to-date answer to the question that brought this to my attention and I updated my own answer. However all the other answers are completely out of date and no longer useful. Anybody that finds this question has to scroll past pages of highly-voted out-of-date answers to get to something that works.

How should this situation be handled? I can imagine several possible solutions:

1. Comment on each out-of-date answer and hope the author comes back to update it.
2. Edit each out-of-date answer to remove the broken link and put a notice at the top of the answer that it is no longer any good.
3. Flag each out-of-date answer so that a moderator can remove it

Answer 1

This is one of the reasons that we discourage product recommendations on super user.

In many cases the author is gone so pinging the author might not be a good solution on its own.

To me

• If its a completely obsolete technology that someone is unlikely to effectively use, and relies on a dead link to work, closure of the question is the right answer.

• If a resource has moved, replacing it with the new link is a good idea. Sometimes forks are of ambiguous officialness, and we had someone try to replace all the links to a fairly major project to their own fork of it on SU, so some form of documentation/discussion first, via comments or better yet meta might be nice.

• If its possible to 'replace' the link with an archive link and still have the answer usable, this would be a decent alternative.

• if the accepted answer is 'dead' - a comment or notice in the answer itself might be useful. Sometimes dead sites get converted to spam portals, in which case deletion would be the best option.

• if the best course of action is unclear - a meta post discussing the question and its answers would be a decent form of governance/documentation of what was done/decided. Sometimes a member of the community might have an idea on the first three options. If the first option, of closing the question is incorrect discussion would be fruitful too.