What do we do with questions about a different version of a spell but with the same D&D edition?

Question

What do we do when a question asks about a particular D&D spell/feature/race/skill/etc that's been published twice in official D&D books?

As far as I know, it's only happened here (but I have not browsed any other system than dnd-5e, so these might also be happening in other systems)

In this case, the linked question specifically asks about the Elemental Evil Player's Companion version of Catapult. Two years later, Xanathar's Guide to Everything released a newer version of Catapult, and the question got an answer based on that version.

I don't think the answer is relevant to the question about the EEPC version of catapult, so I flagged it. But how do we signal that a question is for a specific version in a particular book?

A couple of ideas come to mind:

• Add a [$book] tag (maybe something like elemental-evil?)
• Edit the question to signal that they know there's a newer version of the spell, and is only interested in this version.

Answer 1

Officially, there aren't different versions of the same thing in 5E — the later versions supplant them.

In this interview, Jeremy Crawford says:

The spells from Princes of the Apocalypse that reappear in this book ... some of the spells have been revised, and in some cases, we've expanded which classes are getting those spells. So there are a few spells that, in Princes of the Apocalypse and the Elemental Evil that maybe only one class got that now, several classes get. And when it comes to revision, in most cases, we've just clarified things in the spells. But in a few places, we've also enhanced the spells, because there were a few of the spells that just weren't quite hitting their marks, and so we improved them.

And, in the official November errata, we have this:

Among the new spells in Xanathar’s Guide to Everything are some that originally appeared in Princes of the Apocalypse and the Elemental Evil Player’s Companion, an online supplement. When adding the spells to Xanathar’s Guide to Everything, we made refinements. Those changes are reflected in the following two PDFs:

Princes of the Apocalypse Errata

Elemental Evil Player’s Companion

Note that in the second case, the whole supplement has been updated. So, in the specific case of "Oh, I want the Elemental Evil version!" — now the updated version is that version.

Of course, a table could decide to play with the older rules and ignore the errata or updates. In those cases, the question should state that explicitly. But that's a corner case that I don't think we need to do anything special about in general.

Answer 2

Flag answers that fail to answer the question because of stuff like that. If a querent specifically says "I want to know how this works using the second printing of the 8th edition of the rulebook" or whatever and someone answers with an answer that isn't from that specific version, that's not a real answer to the question and it should be deleted. It's just as unhelpful as when someone puts an answer on a question that's not even for the right system, and we delete those.

Note that there's a subjective judgement here between answers that clearly understand they are sourcing advice from a different edition/game/what have you and answers that clearly don't realize D&D 5e isn't the only RPG system ever. If an answer says "There's no information from [desired edition], but there is information from [other product] and I think that that information should work well for you in this case because [reasons why this isn't terrible]." that's an answer, and if it's nonetheless completely unhelpful it's got to be downvoted before it gets deleted.

We don't need a tag for this, yet, because people rarely specify they are interested in the interpretation of material that has been officially errata'd in the absence of said errata, and when that's a common decision (e.g. ignoring Complete Psionics in favor of Expanded Psionics Handbook) its a sign update material was truly terrible and our community seems to similarly assume said update material doesn't exist unless it's central to the question. If people need a tag for this at some point, they can make one.

Lastly, your cited question isn't really a great example, because it doesn't specify that it's only about a certain version of a spell, but rather uses text from a particular now-updated version. That's very different and referencing the updated material is an excellent response to questions like that.