As noted by AppleInsider reader Gregg Mojica, the latest iAd Producer was pushed out just minutes before Apple's quarterly conference call for the second fiscal quarter of 2013. Three main features were added the the usual iAd creation toolset: iBooks Author Widgets, iTunes Extras and iTunes LP.
Example of an iBooks Widget. | Source: Apple
From the iAd Producer help page:
iBooks Author Widget
You can create an iBooks Author widget for use in your iBooks Author projects. For example, you can create a widget that allows users to stream video from the Internet, draw using their finger, or interact with a timeline.
You can create an iTunes Extras project to provide bonus content (such as cast interviews, bonus videos, or behind-the-scenes photos) for movies available on the iTunes Store.
You can create an iTunes LP project to provide additional content (such as lyrics or photos) for albums you?ve submitted to the iTunes Store. You can create your iTunes LP using a template, or start with a blank project.
Version 4.0 of iAd Producer comes in at 341MB and developers can download the software from Apple's developer website.