NVIDIA is currently releasing out the Android 6.0 Marshmallow update to their original Shield Tablet. The latest Shield Tablet K1 was the first to see the Marshmallow upgrade back in December, which means the NVIDIA is doing their best to keep up with consistent software updates.
Like other major Marshmallow updates, the 4.0 Shield Tablet upgrade will add a variety of new enhancements that will improve the use of the tablet. Some of its outstanding features include better app permissions, Google Now on Tap, improvements on App Standby, enhanced Wi-Fi connectivity along with Android security patches for January. The user interface also includes a few new features like allowing users to employ Google Voice commands through their locked screen, fresh NVIDIA wallpapers, personalization of the Quick Settings menu, as well as new user interface for the Camera app.
NVIDIA also recommended that users making use of an SD card, should perform a full back up of all their data, because the Android 6.0 Marshmallow update alters how the expandable memory functions. The update features quite a few changes, both minor and major, for more details click here
The download for the Shield Tablet upgrade 4.0 is currently available, just go to Settings >> About tablet to install it.