Well, that didn't take long. Little Witch Academia 2 was on Kickstarter for 3 hours before being fully funded. The page lists no stretch goals, although it sounds as if they're coming soon. Beyond that, Trigger's Facebook page also suggests they're looking into dubbing the new animated short.
You might recall that Little Witch Academia is a bit like Japanese Harry Potter, except cuter. Here's the pitch from the Kickstarter for LWA2, if you'd like to watch it:
What is concretely known is that the new episode will be at least 20 minutes, and will be subtitled in 7 different languages. The Kickstarter says they'll add 15 minutes if they get "enough" support, although it's unclear how much exactly that requires.
The original, must-watch short is here: