CS50 registration

Hello,

  So, I enrolled and paid for the certificate for the CS50 class and I enrolled in December 2020 and it’s 2021 now and it shows on my laptop that I need to go through with the 2021 version. I want to know if I have to re-register for the class and repay if I haven’t been in the class for a whole semester. Also will my projects I competed till over to the new version?