Does the course exam require the upgrade/extra payment?

I completed the practice exam but didn't see the course exam coming up. Instead, it was asking me to upgrade which entails extra payment beyond the annual plan that I have paid for. If I don't upgrade, does I mean I can't take the course exam? If I don't take the course exam, I assume I can't get the certificate of this course and thus can't complete the career track (this is a required course for Data Scientist career track). Thanks.