Today sees the launch of a new exam for the VCAP5-DCA certification, VDCA550 which is based on vSphere 5.5.
The original VCDA510 exam based on vSphere 5.0/5.1 remains available, so be careful when you book the exam to make sure you're registering for the one that matches the software versions you've used during your preparations.
This is the same approach as VMware took for VCP5-DCV back in January: http://vmwaretraining.blogspot.co.uk/2014/01/vcp5-dcv-now-updated-for-vsphere-55.html
Passing either of the exam will meet the requirement to become VCAP5-DCA certified, the pre-requisite certifications remain the same.
The recommended training class vSphere: Optimize & Scale was also recently updated for the 5.5 release: http://mylearn.vmware.com/mgrreg/courses.cfm?ui=www_edu&a=one&id_subject=46566
You can read more about the new exam and access the blueprint for both the VCDA550 and VCDA510 exams here: http://mylearn.vmware.com/mgrReg/plan.cfm?plan=47316&ui=www_cert
Josh Andrews from the VMware Certification team has created a post on his blog describing the new lab environment and blueprint changes: http://sostechblog.com/2014/04/07/vcap5-dca-update-for-vsphere-5-5/