According to the article written here about "Passive Voice activation for Cortana."
"The one caveat to this feature is when it arrives, it will most likely only work on newer Snapdragon 800 and higher chipsets. The ability to leave microphones on for passive activation is not a trivial thing to enable on any phone (unless you're the NSA, we suppose). That means in designing and enabling this feature, Microsoft may have to somewhat fragment the Cortana experience, frustrating some users who have older hardware."
So MS is promoting this phone knowing it won't support new updates...Nice. That should sell some phones.
"The one caveat to this feature is when it arrives, it will most likely only work on newer Snapdragon 800 and higher chipsets. The ability to leave microphones on for passive activation is not a trivial thing to enable on any phone (unless you're the NSA, we suppose). That means in designing and enabling this feature, Microsoft may have to somewhat fragment the Cortana experience, frustrating some users who have older hardware."
So MS is promoting this phone knowing it won't support new updates...Nice. That should sell some phones.