Release date for State of Decay 2 and gameplay details will be announced during E3 2017
E3 is a very popular gaming event, and State of Decay 2 developers already teased some announcement for year 2017. The next June we will know the exact release date and also have some new gameplay details of Undead Labs new game. This may be the earliest teaser of E3 announcement in videogames history.
From announcement on E3 2016 we know that State of Decay 2 will offer MMO-style cooperative elements in open-world, filled by zombies. Progression system from the original game will also see great improvements.