How should software related SE sites handle drastic version changes?

Question

A situation has come up on Drupal Answers that I wanted to bring to the larger SE audience. I am not asking for how to solve our particular problem, but how this type of problem should be handled on SE in general.

For those that don't know Drupal Answers, it is the SE site dedicated to an open-source content management system called Drupal. The site deals with all sorts of questions, from code (i.e., developer oriented) to users (i.e., site users / builders).

You probably could have put two and two together there, but bear with me.

DA discourages the use of version tags, much like many other SE sites. They should only be used when the version number is specifically needed to answer a question.

For example, "How do I create a user?" doesn't need a version tag; it's a rather generic question from a Drupal standpoint.

A question like, "How do I do an EntityFieldQuery for users who are blocked?" probably needs a version tag.

A little over a year ago, Drupal 8 came out. This version was a radical rewrite of the software. This means that a lot of questions have radically different answers depending on version <= 7 and >= 8.

For example, "How do I add a JavaScript library to my theme?" is a generic question, but two totally different answers for Drupal 7 and 8.

Why is this a problem? We have about six years worth of questions and answers. A lot of questions that are starting to come in are question duplicates, but would have radically different answers. Nearly every question has the comment now "What version?" and someone edits this into the question and/or tags it, even on the generic questions.

There are two options that are being discussed.

1. Close as duplicate, and add the Drupal 8 answer to the older question. The problem with this results in a lot of closures, and it makes finding answers to current problems difficult.

2. Allow the new questions, and tag them. The problem with this is that we now have lots of nearly identical questions, other than tags. And, we have lots of old questions w/o version tags. And when Drupal 9 comes out, it would require mass tagging, or worse more versions of questions if Drupal 9 is radically different than Drupal 8.

I have tried to lay out the situation, and provide some (contrived) examples. Please don't dwell on the examples above; they are really just to try to illustrate the problem.

What should a software-related SE site do when a drastic change happens between versions that would potentially cause a split of questions between old and new versions?

Answer 1

The ultimate solution might be to bring Documentation's flexible versions to Q&A. That would allow the same question to be answered for multiple versions of the software without confusion.

<!-- if version [gte 8] -->
Drupal 8 answer.
<!-- end version if -->

<!-- if version [lte 7] -->
Legacy answer.
<!-- end version if -->

But we are still aways off from porting Documentation to Stack Exchange sites and there's no support (yet) for Documentation versions on Stack Overflow Q&A. Of course, you can also just do this by hand:

If you are using Drupal 8 use this code:

. . . 

For older versions, you're stuck doing:

. . . 

But that really only makes sense for new answers. The problem, as you point out, is there's a corpus of knowledge that might or might not be outdated. It's going to be confusing no matter what.

So I think Drupal Answers needs to break down and start using version tags. Just as you can ask the same question with c and c++ on Stack Overflow, there should be space for users to ask seemingly identical questions about the new and old versions of Drupal.

For the immediate time period, it's most practical to tag new questions by version if the resulting answers would be different. Obviously askers will not be able to do this on their own, so you might get questions tagged as a particular version that have answers applicable to all versions. The secret with tagging is to use edits to clean up after askers who, by definition, don't know all the ins and outs.

For the long term, well, it depends on how many questions actually are specific to a particular version. I'd probably avoid massive retagging efforts and instead rely on people finding these questions organically. I bet most Drupal developers have already discovered there's tons of outdated information out there because of the new version. It's just the cost of doing business with actively maintained software.