Just after Sony Mobile release the much waited Android 6.0 Marshmallow update to Xperia Z5 series they also released the same update for Xperia Z3 Plus and Xperia Z4 tablet from the same build number 32.1.A.1.163 as on the Xperia Z5 series. At the moment update is live on both the Xperia Z4 tablet variants Wi-Fi (SGP712) and LTE (SGP771) and for both single and dual sim variant of Xperia Z3 Plus. If you need to see the change-log please go to our Z5 Marshmallow post.
Sony Mobile has removed the Stamina mode in this update, but it is expected to bring the stamina mode on the future firmware update. Also Sony mobile has included the February 2016 security patch on the new update. Many users (specially Xperia M4 Aqua 8GB users) thought that marshmallow update will bring the adoptable storage option.It is a shame that Sony Mobile hasn't included it in the update. So you cant use a Micro-SD card to expand you internal memory.
Just be patient until the software update notification appears on your device. So if you've got the update please do post some screenshots and any information regarding the update.