After HTC and Motorola, now T-Mobile has released a list of devices on its network that are slated to receive the Android 6.0 Marshmallow update. The list includes the HTC One M8, M9; LG G3, G4, G Stylo; Google Nexus 5, 6, 7, 9; Samsung Galaxy Note 4, Note5, Note Edge, S5, S6, S6 edge, S6 edge+, and Tab S2. The magenta carrier explains that the update process consists of three stages: Manufacturer Development (point where the carrier and the device manufacturer agree to support a new software update), T-Mobile Testing, and Completed (update launch approved). Currently, aside from the Nexus devices, all other devices in the list are at the first...
Source: http://www.gsmarena.com/these_tmobile_devices_will_get_android_60_marshmallow_update-news-14323.php
