Later today, Google will formally announce Android 6.0 Marshmallow, along with two 'hero' devices showcasing the features of its latest OS. But just hours before the next version of Android is officially unveiled, T-Mobile has only just updated two of its devices to a version of the OS that Google put together last year.
The Samsung Galaxy Note 10.1 (2014 Edition) and Galaxy Tab 4 have both been stuck on Android 4.4 KitKat on T-Mobile, long after Google announced Android 5.0 Lollipop in October 2014.
Since then, newer versions of Lollipop have rolled out - but instead of upgrading its devices to one of the very newest Android releases, T-Mobile has instead upgraded them to Android 5.0.2, which was originally compiled in December 2014. T-Mobile's update for the Galaxy Note 10.1 (2014) brings its firmware up to P607TUVUBOI2; and the Galaxy Tab 4 goes up to T337TUVU1COH5.
Along with all the other bits that the Lollipop update brings over KitKat, T-Mobile has also included a fix for the Stagefright vulnerability in Android.