Owners of the global version of the Sony Xperia Z5, along with the Xperia Z5 Premium and Xperia Z5 Compact, should be on the lookout for an update. The company is rolling out a new version of its software that will upgrade them to Android 6.0 Marshmallow.
The unofficial Xperia Blog states:
Last week we saw the update land on Japanese NTT docomo Xperia Z5 devices, but today the update has started for the global variants. At the time of writing, firmware build 32.1.A.1.163 is currently live across all variants of the Xperia Z5, but we are also starting to see the firmware seed for the Xperia Z5 Premium and Xperia Z5 Compact.
The update also reportedly includes the February security updates from Google. If you own one of these phones, be aware it may take a few days for the Marshmallow update to reach your device.