So, there is a lot of emphasis on Android N (also known as Nougat or Android 7.0), but we probably won't be seeing that until at least September with Google's new Nexus devices. There are still some Android devices that still have not received their Android 6.0 (also known as Marshmallow or Android M), and one of them is Sony. This is the information that is known about Android M Version 6.0 Marshmallow and Android Nougat Release Date for Sony Xperia Z5, Z4, Z3, and Z2 on Sprint, AT&T, US Cellular, T-Mobile, and Verizon.
According to Yibada, there are reports saying that the Z5 series, which includes the Z5, Z5 Premium, and Z5 Compact, has received the Android Marshmallow update. Believe it or not, it is difficult to discover what happens with Sony, as most websites devoted to telling viewers what Android devices have Marshmallow don't seem to report on Sony.
So, it is good that the Japanese company's flagships have the latest version of Marshamllow (or the latest before Android Nougat is released), but what about the other flagships from years past with the Xperia Z3 and Z2 series. There is the Android Marshmallow update is live for the Xperia Z3 Compact (D5803), Xperia Z3 (D6603), and Xperia Z2 (D6503) with a firmware build number of 23.5.A.0.570. There are reports from Tech Radar saying that Marshmallow to come to Xperia M5, Xperia C5 Ultra, Xperia M4 Aqua, and the Xperia C4.
As far as when Android Nougat will be released, there are speculations that the Android N update will be released in the third quarter of 2016. Considering all of the delays that are associated with the latest version of Android on Sony, it will probably more realistically be showing up in 2017.
So what will be the first Sony devices to receive Android N? Chances are, it will be the Sony Xperia X devices first. Then it will be the Z5-branded, with the Z4 tablet, and the Z3 series. Given that the newer Android devices receive the upgrade first, it will probably happen in that order.
The best and only advice one can give a Sony user of a newer device in the United States is to see if you can't get the OTA (Over The Air) download of Android Marshmallow now. Just go into the "Settings" and "System Update" to see if the upgrade is available. The upgrade may not be available depending on your carrier like T-Mobile, Sprint, US Cellular, AT&T, and Verizon. Feel free to leave a comment here saying whether or not you received your Marshmallow on your Sony device, as well as what carrier that you subscribe to.