In ConfigMgr 1511 you have a new maintenance windows when you open the site server properties. That’s NOT for traditional software updates but for the new ConfigMgr Updates and Servicing model. You get to the maintenance windows in the Administration workspace, Site Configuration, Sites. Right the primary site and select properties. In the Maintenance Window tab, create a maintenance window (and make sure you call it something like ConfigMgr Dynamic update Only).
I did a few tests and the maintenance window do not apply to traditional software updates. According to my tests normal software software updates will still apply unless you create a collection based maintenance windows.