User blog comment:Jmcdavid/Pokemon Sun and Moon - My Thoughts/@comment-9442368-20160816002017/@comment-25451319-20160816005444

Well, someone else pointed out to me that it wouldn't be like them to just drop such a huge game mechanic. So, it's gonna probably be in the postgame, at the very least.

What's the thing about Popplio's supposed final evolution that has you thinking that? I don't think I ever saw anything about that one.