This is a good news / bad news situation: Pixar has announced that the planned release dates for Toy Story 4 and The Incredibles 2 have been swapped. The sequel to The Incredibles will now be released on 15 June, 2018 in the US, and the fourth installment in the Toy Story franchise will be released on 21 June, 2019.
The studio hasn't commented on the swap, beyond the announcement itslef:
#TheIncredibles2 hits theatres on June 15, 2018, and #ToyStory4 on June 21, 2019! 💥💪🚀🌵 pic.twitter.com/D9EsXrhJNs— Disney•Pixar (@DisneyPixar) October 26, 2016
This might mean Toy Story 4 is having trouble during its production, as it is now the second time the film has been delayed (it was originally supposed to open in 2017); conversely, this probably indicates that everything is going smoothly on The Incredibles 2.
Pixar will have two films out before The Incredibles 2 opens (Cars 3 and Coco, both arriving next year).