Sprint Users

I have a nexus 6 on Sprint and I'm curious what build Google sends out to Sprint Users. Is it the MMB build or the MOB build? I upgraded to nougat for the beta preview but I unenrolled after having some BT issues. I was on the August build of marshmallow prior to upgrading. Since downgrading over a week ago I've been stick on the July build of Mars allow and it's the MMB build. Just wondering if I got downgraded to the incorrect build and that's why I'm not getting OTAs anymore. Thanks