From DART website:
Shuttle Bus to Sub for Las Colinas APT During Construction, Effective Tuesday, September 5, 2017
The Las Colinas Area's Personal Transit System (APT) is growing in popularity, with a new station coming this Fall. And while that new station takes shape, a portion of the system will be out of service, beginning Tuesday, September 5, 2017.
For obvious reasons I am glad they did not choose to do this over the summer..... say, in July.