Will someone releases a stock android(Vanilla/AOSP) for mx4\5?

Is someone working on it, or the best alternative is cm12?

No Marshmallow for the Tablet Z as Sony releases supported devices for update...

Looks like we are out of luck for the new Marshmallow update next year...
http://www.androidauthority.com/sony...update-647255/
Oh well 5.1..1 still rocks...