Although Google has already started testing Android N with developers, Android handset makers are still busy updating their wares to Marshmallow. Case in point: LG, and its G3. The flagship smartphone from 2014 is now receiving the update to Android 6.0 Marshmallow both on AT&T and T-Mobile, according to multiple reports from owners. T-Mobile's model isn't currently enjoying an over-the-air rollout of the update, so to download and install it you'll need to use LG's desktop software. Even so, the new release may not yet show as being available for everyone. If you bought your G3...
Source: http://www.gsmarena.com/marshmallow_is_now_out_for_the_lg_g3_on_at_t_and_tmobile-news-18015.php