Sony has updated its support pages to indicate the fact that at least six of its devices will not be receiving updates to Android 5.1.1 Lollipop. Instead, these will jump from 5.0 straight to Android 6.0 Marshmallow.
The devices in question are the Xperia Z3+, Xperia Z4 Tablet, Xperia C4, Xperia C5 Ultra, Xperia M4 Aqua, and Xperia M5. The support pages for all of these now list Android 6.0 Marshmallow as the next version of the OS that they'll get, even though they're all still running 5.0.
Given the fact that Marshmallow is already launched, this makes sense. If Sony were to work on the Android 5.1.1 update for these devices first, and only then start developing Marshmallow, you can imagine how late that would come out. Even so, you probably shouldn't expect any of them to taste Marshmallow this year.
It's unclear why Sony hasn't already released updates to Android 5.1.1 for these smartphones and the Z4 Tablet, but now it's certain that it won't go this route at all.