After a long wait, Sony has started rolling out the Android 6.0 Marshmallow update globally for Sony Xperia Z5. This was reported earlier by some reddit users. Earlier, Sony rolled out the Android M update for Sony Xperia Z5 only in Japan. According to the details, owners of the Xperia Z5 Premium and Z5 Compact will also start getting the update shortly.
After Japan, Sony started rolling out the Android 6.0 update for Xperia Z5 owners in Thailand and Russia as well but now a lot of people, round the globe, have started sharing that their Z5 is getting the update which suggests that the long wait is over at least for the Xperia Z5 trio users.
On the other hand, despite being the steady update till now, Android 6.0 update rollout process is much slower as compared to the Android 5.0 Lollipop. Although most of the OEMs have started rolling out the updates if not earlier but still the process is painfully slow. Likewise Sony is rolling out the Android 6.0 Update for its Xperia Z5 series despite the Android 6.0.1 update is already available.
The latest Reddit thread suggested that the update is available in Austalia, Malaysia, Ireland and Austria but definitely it will begin in other countries sooner if not started yet. So if you have not yet received the update on your Xperia Z5, keep checking as it can be only a matter of time.
The latest Android 6.0 Marshmallow update for Xperia Z5 will improve the battery life with the help of battery-saving Doze feature of the OS. There are some other performance benefits as well with the update, so you must try it once you get the update.