Apple releases iTunes 9.2.1 with an improved performance iBooks 1.1.1

The update of iTunes 9.2.1 is shadowed with the event Apple giving free bumper to iPhone 4 users. However it's worth to mention that this update have major improvement for iBook. Now you can enjoy a much performance improvement when reading books in PDF format. You also can double tap within a book to see it in more detail. And the best, you can try iBook with additional audio and video. Besides iBook improvement, this iTunes update also fix buges and patch some security issues.

However for jailbroken iPhones, it may be a good idea to stay away with this update since there are some reports that some jailbroken iPhones stop working after the update. It's really depended on which method and software you used to jailbreak your phone.