https://www.pcgamer.com/amazons-fallout-76-preorder-age-originally-indicated-a-july-release-date/

Fallout 76 doesn't have a release date yet—that will presumably be revealed at E3—but it could arrive sooner than anyone expects. The Amazon preorder page currently lists the launch date as December 31, 2019, but as Massively Overpowered observed, when it first went up it carried a "get it by" date of July 31 2018. 

Image source: Massively Overpowered