LG G4 under AT&T is reportedly up for the official over-the-air release of Android 6.0 Marshmallow next to Sprint and US Cellular. Per previous reports, G4 of AT&T might be updated in February.
T-Mobile is the latest mobile carrier in the United States to have been reported to release the Android 6.0 Marshmallow update to LG G4 units, following releases of Sprint and US Cellular. More details here.
Sony Xperia Z3+ is expected to receive the Android 6.0 Marshmallow update in February, as a Canadian hints a new schedule of release for its devices. The update will come out with a bunch of improvements.