No word on the launch date or platforms but 2020 seems likely but when I know more i'll drop the word here.
*An all-new presentation...
When Drill Knight and his dastardly digging crew blast apart Shovel Knight’s peaceful campsite and steal his loot, he grabs his trusty Shovel Blade and starts tunnelling after them! Meet new friends and foes, visit strange lands, and outfit yourself in your quest to keep the entire land from collapsing underfoot! Jump, slash, and dig your way down an ever-changing chasm of mystery in Shovel Knight Dig, an all-new Shovel Knight adventure!
More information about the final update to Shovel Knight and it getting a physical release on Switch: https://yachtclubgames.com/2019/08/upcoming-shovel-knight-features/
I played the original campaign and then I’ve been waiting for the whole shebang to release before diving back in for the other campaigns. I’m pretty excited for that. As for Dig? Sure, it looks fun. A very different kind of game.