My 2013 Moto X, bought in early 2014, got left by Google/Moto/Verizon on the 5.whatever that doesn't fix Stagefright.
Until I switch away from Verizon, I stuck my already activated SIM into a Nexus 5x -- the first Nexus to work on Verizon's network.
That Nexus 5x just got the upgrade to Android 7. Because the update is shipped directly from Google and Verizon has no control over it with respect to my independently acquired Nexus 5x.
At the time I bought the Moto X, from a Motorola then owned by Google, Google/Motorola/Verizon was promising that this new ownership/alliance would ensure timely updates. Yeah... so much for that. Updates came slower, and all too soon choked out.