There are only two certification available for PCSA at this time, 8 and 8.4. There is not a 8.3 version. I think you may be referring to an update we made to the System Architect Essentials 8.1 course. We came out with an 8.3 exercise update. The content was still 8.1.
Here are the two certifications available right now:
To take the PCSA Version 8 Certification you will need to return to the old site. Once there you will need to search for the System Architect Essentials course if it does not show up on your Dashboard.