Over three months ago, HTC began upgrading the One M9 to Android 7.0 Nougat. However, at the time, the manufacturer only released the update for unlocked models of the device, making it clear that owners of carrier-locked variants would have to wait until "early next year".
Now, T-Mobile US has confirmed that it is testing the Nougat update for the One M9. Unfortunately, that's the only information that it's provided so far - the carrier hasn't yet revealed exactly when it expects the update to become generally available for the device.
T-Mo released Android 7.0 for Samsung's Galaxy S7 and Galaxy S7 edge last month. Along with those two devices and the One M9, the carrier announced in August that it would also bring the Nougat update to six other handsets.
It's now been almost seven months since Google made the first Android 7.0 release officially available. So far, just 2.8% of active Android devices are running Nougat builds.