Motorola is one of the companies that has been silent about pushing monthly security updates.
The Droid brand phones are notorious for being among the last of their generation to get updates at all, and I believe I recall only critical security patches being pushed (like the Stagefright patch which came out pretty delayed last fall for several Droid models.)
If Motorola does monthly security patches at all, I expect it will be for their unlocked Moto brand phones (the Moto X models; the Moto G models; maybe the Moto E models) and the Droids will not. I suppose anything is possible, but I suspect that Motorola is really overwhelmed just trying to keep up with update support and development of their upcoming phones and just doesn't have the resources to push timely monthly security patches, particularly with this phone and the Maxx 2.
What I would hope is that somehow Google figures out a way to design Android so that they can push security patches to phones like these without manufacturer involvement. But I see that perhaps with future phones, not this one.