I reached out about an issue with the app in October 2021. As a student, obviously, a prompt response is needed to address a current problem. I got a response weeks later. The response was defensive and not helpful for the issue that still existed. I am not a fan of ebooks anyway but -for this course. It was the most cost-efficient option. NOTE: The search feature does not highlight each parameter found by page number, so you never know where the search item is without going through the entire list. NOT HELPFUL.