According to the product manager of T-Mobile, Des, who confirmed in his tweet that Operating system update should start to rollout this week.
If you have automatic updates on, you need not worry, you will get a notification when the update hits your device, but if you have kept it turned off or if the update notification doesn’t arrive at your device, you need to check it manually by going into Settings > About > Software update.
The Nougat update will bring features such as split-window mode, notification controls, improved menu settings and better user interface on Samsung Galaxy S6 and S6 Edge.
Interestingly, other carriers such as Verizon and AT&T released Nougat update for Samsung Galaxy S6 and S6 in April itself. Also, T-Mobile released the Nougat update for Samsung Galaxy S6 Edge Plus last month.