iTunes 9.1 upgrade is now up online and you can install it on both Mac OS and Windows. The new version adds sync and management support for iPad, which launches in three days.
It seems Apple decided to put an Easter egg within the upgrade preventing some jailbroken iPhones and iPods from syncing.
The iTunes update comes just a day after the official Mac OS one, which also raised some alarms.
All the iPad users should update to iTunes 9.1, because they have no choice.
The iPhones and iPods users may want to hold on the upgrade until further notice, since user reports show the latest iTunes won’t sync with jailbroken devices.