Folks in Turkey who own the Sony Xperia Z5 can wake up this morning to some tasty Marshmallow madness. Sony started pushing out the Android 6.0/Marshmallow update in that region. There's no word when the rollout will start pushing to other Xperia Z5 devices internationally, but we expect it won't take too long.
Sidenote - this update is only for the Xperia Z5 standard. The Compact and Premium have not received it at the time of this post.
Here's a link to our dedicated Sony Xperia Z5 section for further discussion: Sony Xperia Z5, Z5 Compact & Z5 Premium