Nowadays, the ‘older higher-end’ devices like Sony Xperia Z2, Z3 and Some HTC devices are getting Android Marshmallow update, along with the recently launched smartphone. This is the best proof for that the OEMs have not considered older devices are really junks, because those devices were their hitmaker flagships once. Moreover the Sony, Lenovo, HTC and other manufacturers, LG is now giving the latest OS upgrade from Google. The LG G3, which was released on mid-2014, is now getting Android Marshmallow update Over-The-Air.
The Marshmallow update for LG G3 is currently given only to the users who are using A&T and T-Mobile variants of device. Update for T-Mobile device currently not getting OTA, you need to flash it via LG PC Suit connected via OTG Cable. And the AT&T variants seems to have an OA update, as per the users’ experiences.
Also it is said that the update is given only to the selected users to test it, and the official version for everyone will run out soon. Anyway, have a try yourself on your LG G3, if you’re a subscriber for AT&T or T-Mobile, via both OTA and PC Suit.