Navision Attain Certification

Dear friends, What happend to the certification pre-requisite exams Before and after the aquisition of MicroSoft ? We were under the impression that for any certification Navision overview exam is a pre-requisite.But,recently we went through the partnerguide’s website,there it is mentioned that for any certification Navision Attain Essentials is pre-requisite.Do we need to write Navision Overview exam or we can start with Essentials exam directly for any certification?Is there any link between Overview exam and developer licence file renewal? with regards rajasekhar