Sony has updated its support pages mentioning the name of six devices which will directly be updated to Android 6.0 Marshmallow from Android 5.0 Lollipop leaving the update 5.1.1 behind. The devices that will receive the Marshmallow are Xperia Z3+, Xperia Z4 Tablet, Xperia C4, Xperia C5 Ultra, Xperia M4 Aqua, and Xperia M5.
The support pages lists that now these devices can get Android 6.0 Marshmallow straight from Android 5.0 Lollipop. As Marshmallow is already on a roll out so this makes a lot of sense. If Sony will start working on 5.1.1 update first, it will take quite a long to get to the Marshmallow. Even now, you won’t expect the update to get rolled out to these devices this year.
It is, however, unclear that why Sony has not updated its smartphones even like Z4 Tablet to 5.1.1 to date. But it is very clear that it won’t go on this route now.