How to answer old questions

Question

There has been some discussion lately about old questions that don't adhere to rules that are newer, such as flexible I/O. My question is simple: how should we go about answering these?

Here are some ideas I have come up with:

1. Write a new question and close the old one as a duplicate, or freeze it
2. Answer the old question under the new rules, and mention that in the answer
3. Answer the old question under the old rules
4. Update the question's rules, then answer it (Thanks @WheatWizard!)

Answer 1

It really depends on the specific challenge in question, and so there's not really a catch-all answer to this question. Some guidelines I would suggest:

• If the challenge doesn't explicitly require use of the old rules, an answer using new rules is valid, but you probably should mention the relevant rules in the answer.
• If minor edits (e.g. removing a cumbersome I/O format that isn't critical to the challenge) would bring the challenge in line with our current rules/standards, then that's probably a good option.
• If the challenge would require major edits (substantially changing the core of the challenge to comply with our modern rules/standards), then it's probably best to write a new challenge and have the old closed as a dupe.

When in doubt, start a meta discussion about the specific challenge. A meta discussion should definitely take place before editing or rewriting a challenge.