While Sony has yet to post a full changelog, multiple users took to XDA-Developers and Reddit to report that this new update brings along several noteworthy improvements. For instance, the camera is said to load much faster now, the fingerprint sensor is said to be more accurate, and the overall performance of the device is allegedly improved.
If you're already rocking the Sony Xperia Z5 or the Xperia Z5 Compact, your phone should be getting this new update shortly. It appears that checking for updates through Sony's PC app is more efficient than waiting for the OTA update to reach your device.
Just recently, the international version of the Sony Xperia Z5 Compact has quietly landed in the US through Amazon, where the phone is available at about $430 unlocked. This version, too, will probably get this new update in the following weeks.