With Android 6.0 (also known as Android M or Marshmallow) rolling out to Google's own Nexus devices already, the big question is why hasn't it come to most of the devices from companies like Motorola, Samsung, HTC, LG, and Sony. Sony's Xperia series has made quite a mark on the Android community, and this is what is known about the Android Version 6.0 Marshmallow Release Date for Sony Xperia Z5, Z5 Compact, Z5 Premium, Z4, and Z3 Series for carriers like Sprint, Verizon, AT&T, T-Mobile, and US Cellular.
Sony has often had a reputation for being slow when it comes to Android updates, at least, when it comes to other smartphone manufacturers. Gotta Be Mobile reports that the company did open source the Android 6.0 update, which would allow developers and ROM makers from the Android community to build versions of Android Marshmallow for select devices. This could mean that Android Marshmallow could arrive sooner rather than later, but there isn't any word on when.
The list of devices to receive the Android update is enormous, with some from 2013. It is pretty rare in the world of Android upgrades for any device over two years old to receive an Android update. There is even a report on XperiaSony (which may or not be a reliable source) saying that the Z1 could be receiving the update, which would be very unusual.
The first that probably will receive the new Android update are the flagships of the Xperia Z5, Z5 Compact, and the Z5 Premium. In fact, Know Your Mobile says that Sony will be updating the entire Z5 line-up in January, which seems like a good enough estimation as any. This news comes from a reliable Twitter tipster named @Ricciolo who said: "an update has come yesterday, #marshmallow READY next month for #sony #z5 family..older #xperia models to follow shortly".
So what older models will those be? After the Z5 series will be the Xperia Z3+ and Z4. What follows will be the rest of the Z3 series with the Z3, Z3V, Z3 Compact, Tablet Compact, and more. Other devices to receive the update will be the Xperia Z Ultra GPE, the Xperia C5 Ultra, the Xperia M5, and the Sony Xperia M4 Aqua.
Android Pit also states that when a Sony device could receive the update to Version 6.0 will also vary directly on the carrier, which in the United States would be Verizon, US Cellular, Sprint, AT&T, and T-Mobile.