Hi Jon,
When trying to open a .mpp file that has hyperlinks added (I am not sure if the hyperlink is added in Hyperlink column or in a Text column) I get:
java.lang.ClassCastException: class java.util.UUID cannot be cast to class java.lang.String (java.util.UUID and java.lang.String are in module java.base of loader 'bootstrap')
at org.mpxj.Task.getText(Task.java:2519)
I tested with MPXJ 15.1.0
Cheers,
Tiberiu