This is what Clem (Clement Lefebvre) has to say about that:
> I can’t say yet. It’s part of the goals. I mean, everybody wants a safe and trivial upgrade path between 17 and 18. It’s something we’ll have in mind when working on 18. It will be possible for sure. We can make it trivial very easily.. but will it be safe enough for us to recommend it? That’s the big question and it depends on a lot of things which aren’t decided just yet. We’ll give it our best shot and if we can’t make it as trivial as we did for 17.x upgrades, at least we’ll document it and guide people through it. With the slower LTS pace, this has become more important and we’re fully aware of that.