CommentStreams:37c91f7088efaf35474d92c832e2d14e
From The Lost Media Wiki
However, I would suggest to take that tweet with a grain of salt because there is no official announcement or statement from Disney itself that they will continue production on the film and there are currently no news articles on the internet saying that it's true.
On an unrelated note, if the film never makes it out of cancellation, Giraffic/Gigantic will always be a Weaselton exclusive bootleg DVD and he is the only person in Zootopia who has a copy of the movie! (I know it's an Easter Egg scene, but the film's cancellation just makes the joke funnier).