Hey Henri,
We don't yet have this built into wyBuild. The way we recommend delivering "traditional" updates is just releasing an installer of your latest version.
Or you can use %updatepath% in tandem with -server to install updates from a localpath. See: http://wyday.com/wybuild/help/wyupdate-commandline.php
But I don't that was what you were looking for. wyBuild doesn't currently output patch *.exe files. Just patch files in a format wyUpdate can read.