This update is recommended for owners of MacBook, MacBook Air, and MacBook Pro with Mini DisplayPort. The update addresses an issue where some standard definition purchases from the iTunes Store do not play on some external displays.As pointed by Dana, Macrumors summarize the current situation: This latest update appears to remove the HDCP enforcement on standard definition content, which means that current movie content purchased or rented on a Mac should playback unrestricted. While Apple does offer high definition movies for rental through Apple TV, it's not clear when Apple will begin offering this to Mac users.
However, by looking at differences between the new version and the previous one, hackers will most likely find how Apple managed is HDCP protection only via a software solution. This would ultimately allow any Mac users to play and watch HD movies on their Mac, irrespective to the brand of their display or hardware models.
