Hi Philip! Good question, no the ACDX written exam will not recertify the ACMP and ACCP because those lower certifiations are in different technology domains (ClearPass/ Mobility vs Design). If you had an ACDP, then yes the ACDX written exam would recertify the ACDP.
In order to recertify your ACMP you would need to:
a) Pass the ACMP exam on PearsonVue
or
b)Pass the higher level ACMX written exam on PearsonVue
Alternatively, with the new Edge Certification track (See Edge in FAQ for more info) you could earn either the ACSP (Switching) or ACDP (Design) which would then make you an Aruba Certified Edge Professional. The Edge certification is granted to individuals who hold 3/4 certifications (ClearPass, Switching, Design, Mobility) at each level (associate/ professional/ expert).
If you go the Edge route when you earn that third certification, all you have to do is pass the Edge Professional exam on PearsonVue and that will recertify your ACMP, ACCP, and ACSP/DP. Basically one exam to rule them all! :)
I hope this makes sense, if you have any other questions please reach out to us arubatraining@hpe.com!