One of iOS 9's coolest new features isn't yet ready for primetime. Apple today announced that app thinning (or app slicing) has been delayed because of an iCloud bug.

While not formally announced on the WWDC stage this year, app thinning promised to be one of the most effective new features for iOS 9. Thinning allows developers to keep app packages small by allowing developers to mark essential libraries for specific devices. That way, space-conscious users — especially for those stuck with 16GB iPhones — only download the required essential code. However, the iCloud bug, which keeps users from downloading their apps to new devices, is forcing Apple to push universal apps to users for the time being. While a fix is in the works, it's not clear when Apple will issue the update to turn the feature on.