[This is about
native messaging that affects Windows users. You can stop reading now if you don't develop extensions that use native messaging on Windows]
Since their inception, native messaging hosts have received the origin of the calling extension as an extra argument in the command line. On Linux and Mac, this is the first and only parameter. On Windows, the origin is the second parameter and the first parameter is --parent-window=[handle].
Starting from Chrome 55, the parameter will be the first parameter on all platforms. So, if you developed a native messaging host on Windows and use the --parent-window or origin parameter, publish an update that accounts for the difference in parameter order.
See bug
https://crbug.com/651496 and
https://codereview.chromium.org/2271143002/ for more information.