March 2nd 2015 saw the retirement of 4 exams, each of the 2 VCAP level exams for the Cloud and Desktop disciplines:
VCAP-CIA - Cloud Infrastructure Administration
VCAP-CID - Cloud Infrastructure Design
VCAP-DTA - Desktop Administration
VCAP-DTD - Desktop Design
There were some problems with these exams, and with new versions of these exams needing to be developed for the new VCIX certifications mentioned in the 2015 VMware Certification Roadmap, it was decided to retire these older exams.
This would have meant that the VCDX certifications in these 2 disciplines would no longer be obtainable by those who hadn't already gained both VCAP certifications in that discipline.
But, VMware recognised this and dropped the VCAP requirement for VCDX applications for June defences - you can read more about that here:
VMware Communities post about VCDX-Cloud and VCDX-Desktop changes