Quark Software has released the October Update for QuarkXPress 2016, adding macOS Sierra support. It also addresses known issues.
The update is for both Mac and Windows versions of QuarkXPress 2016 and free for all current QuarkXPress 2016 users. It can be downloaded using the built-in Auto Updater in QuarkXPress or downloaded here (http://www.quark.com/Support/Downloads/).