Sony Xperia Z5, Z4 Tablet, and Z3+ get Security Patch update Android security fixes for the month of March – the security patch level says March 1, 2017. Sony did not give an official statement on it so there isn’t yet an official confirmation on it.
January this year, The Nougat update for these devices was first released back. Sony may have finally fixed the audio issues introduced with the Android Nougat firmware. This update includes a fix for the imbalance of top/bottom speakers and low in-call volume fix.