iTunes 11.4 has been released following Apple’s announcement that iOS 8 will be available next week. The GM seed of the software is available now for developers, and the new iTunes update enables syncing with devices running the mobile update.
Many users on OS X Yosemite trying to install the iOS 8 GM seed have run into a serious issue, however. The current version of iTunes 12 crashes after erasing a user’s device, leaving them stranded in DFU mode with no way to actually get back to a usable state (unless they have a Mavericks machine handy). If you are running Yosemite exclusively, it’s probably best to wait for an iTunes 12 update before attempting to install the GM.