T-Mobile testing Android Nougat for the Samsung Galaxy S7 and S7 edge5
And while we have no word on when exactly carrier-locked Galaxy S7/S7 edge devices will be getting Android 7.0, we know that T-Mobile will be rolling it out sooner rather than later. The Un-carrier's website has a page that lists all devices that will get a software update at some point, and that same page also provides the current status of the update. The S7 family's Nougat update is listed with a status of “T-Mobile Testing”, which means that the software itself is being tested to iron out any issues before release.
With that in mind, we're willing to say that T-Mobile subscribers will be getting Nougat on their S7 and S7 edge phones pretty soon, maybe even ahead of other carriers' customers.
The Samsung Galaxy Note 5, Galaxy S6 and Galaxy S6 edge also make an appearance on the list, confirming that they will get Android 7.0 updates from T-Mobile at some point. However, their status is at “Manufacturer Development”, which means that T-Mobile are waiting for Samsung to release the update first, as do all the carriers.
The other devices that are awaiting “Manufacturer Development” are the LG Stylo 2 Plus and the LG V10.
source: T-Mobile via SamMobile