The majority of our clients are Massachusetts residents, which should mean that the due date is 4-17-19.  However, I have some Mass residents showing a 4-15-19 date, others with 4-17-19, and most with 4-18-19.  For non-Mass residents, there seems to be an even mix of due dates showing as either 4-15-19 and 4-17-19. Customer service has no explanation for this.