Build of Viewer for iOS has issues with Info.plist properties not being included properly. Building with cordova build ios deletes these properties. They are added with the config plugin currently. Look into how to fix this, possibly resorting to copying/overwriting Info.plist.

Also check if the pathes for Cordova 6 in the config/native/ios folder are needed.

When doing this also have a look at specifying plugins in config.xml, that is the new Cordova way.