Project Octopath Traveler had a tentative release date of Spring 2018 according to casual mention on the Nintendo UK site, but that mention has been removed and now the game is just slated for 2018. This was either a fault of someone working on the site, or potentially the game itself has been delayed.
Then again, with a complete demo out that feels absolutely fantastic, it would be pretty disappointing to see it delayed. However as Miyamoto once said, a delayed game is good…. okay let’s not go there, as game delays don’t always mean the end product is great. That being said, I’m not too worried about this Switch exclusive at this time. We’ll wait patiently for Square Enix to update us on the release window soon enough.
Source: Nintendo Everything