Beginning with CC 2019 (released 10/15/2018), Adobe has made our license agreement invalid for upgrades. Adobe has announced that a new device-licensing method will become available in early 2019. They have not yet released any information about how this new device licensing method will function, nor have they given a definite release date.
Until this new device licensing method becomes available, Classroom/Lab-licensed Creative Cloud must remain at CC 2018.
Please, take this into consideration when updating Apps like InDesign at home to insure compatibility with lab computers.