Back in December, HTC released the Android 7.0 Nougat update for unlocked models of its One M9. The manufacturer said at the time that carrier-locked variants wouldn't get the update until "early next year" - and indeed, as is generally the case when it comes to updates, carriers have been in no rush to upgrade their devices.
But last week, T-Mobile in the US confirmed that it was testing Nougat for the One M9, and now, the update is finally rolling out. T-Mo's website indicates that the update is still in testing, but Android Police has confirmed that some users have already received it. As always, bear in mind that updates like this one tend to roll out in 'waves', so it may take some time before all eligible devices are able to install it.
The update brings the One M9's software version up to 4.27.531.6, and is just under 1.1GB in size. Along with Android 7.0 itself, T-Mobile's update also includes unspecified "system performance enhancements". Unfortunately, it only includes the February security patches for Android, and not the latest March security update that Google released more than two weeks ago.
Google originally released Android 7.0 seven months ago. The update's rollout to the One M9 on T-Mobile comes shortly after Google announced the next major version of its OS, currently known as 'Android O'.
Source: Android Police