1.4.15 is now live on google play for those signed up for the beta. The beta does not support any of the external skins. They will be updated once it goes out of beta.
Joining the beta:
Join the GMMP beta community: https://plus.google.com/communities/104337252281562680551
Click on "Become a beta tester" under the "About this community" section.
Updates will be delivered through google play.