These two handsets get the usual Android 7.1 Nougat features, apparently without any Sony-exclusive changes. The new firmware also includes the official security patches for April.
http://www.notebookcheck.net/Sony-Xperia-XZ-and-Xperia-X-Performance-get-Android-7-1-1.214560.0.html
Have to say that I am very happy with my Sony XZ to date, especially that they keep pushing these updates out quickly.