A few tweets from Kazu Kibuishi back in September indicate that the film is currently being produced by an external studio. In 2012, a film was announced, but was slated to be live-action with Jayden and Willow Smith taking the lead roles. (Though it's possible that the two announcements are completely different projects altogether, no confirmation has officially been made.)
The new film will be animated, according to Kazu Kibuishi in the following tweets:
Good news? Definitely, as live-action adaptations have proven to be absolutely dreadful for fans. (M. Night's The Last Airbender and James Wong's Dragonball: Evolution come to mind.)
What are your thoughts?