As yet, Google's last push into the tablet market is carried by the HTC Nexus 9, which was released two years ago in November 2014 running Android 5.0 Lollipop out of the box. Since its release, the slate received numerous software updates including a bump to Android 6.0 Marshmallow, and now T-Mobile US is launching yet another software update for the device, pushing the operating system's version to Android 7.1.1 Nougat.
Over the past couple of years, T-Mobile has released several software updates for the Google Nexus 9 tablet, including three Android 6.0 Marshmallow iterations in October 2015, July 2016, and August 2016 respectively. However, the latest software update for T-Mobile's Nexus 9 switches digits and pushes the slate's software version to Android 7.1.1 Nougat. The software package also includes the December Security updates along with unspecified "bug fixes", however, the carrier hasn't yet published a changelog and there are no other details in regards to new features. Nevertheless, generally speaking, Android 7.1 Nougat should technically improve both performance and battery life, and should introduce several changes to the user interface, specifically the apps drawer, the settings menu, and notification shade / quick toggle area. As for what users should know before applying the update, make sure your device has at least 50% battery life left and that the updating process will take place over an active Wi-Fi network to avoid slow speeds and/or unnecessary charges. Another thing to keep in mind is that the update is being deployed in phases. Thus, if you haven't received the update notification yet, you can try triggering the process manually from the tablet's "System" screen in the settings menu.
The Nexus 9 was built by HTC as what appears to be Google's last Nexus tablet before the Pixel brand took over. Released in November 2014, the slate carries an 8.9-inch IPS LCD display with a resolution of 1536 x 2048 and is powered by an Nvidia Tegra K1 dual-core Denver processor clocked at 2.3GHz per core, along with a Kepler DX1 graphics chip and 2GB of RAM. The Nexus 9 is also equipped with an 8-megapixel main camera coupled with a 1.6-megapixel front-facing sensor, and packs a 6,700mAh Li-Po battery rated for up to 720 hours of stand-by time.