With the Expedition Everest 5K starting at 10:00 pm on Thursday, March 31 in the Animal Kingdom parking lot, Disney has announced the Animal Kingdom will close at 7:30 pm that day.
This makes sense as the previously set 8:30 pm closure would make it harder to clear out the park for the runDisney event. It also makes sense given transportation from Disney Resorts to the race is starting that night 8:30 pm. The more Disney can clear out the park and the parking lot before the event, the better.