Starting July 22, 2014, CloudKit will require iOS 8 beta 4 or OS X Yosemite Developer Preview 4. To ensure uninterrupted development of your CloudKit enabled apps, download and upgrade to these versions today.
We will perform a server-side data wipe on all CloudKit public databases on July 22. If you are using iCloud containers with public databases, consider creating a copy of your data so that you can re-upload once the data wipe is complete. iCloud Drive, iCloud
Photo Library, and Mail Drop will not be impacted by the targeted data wipe.
If you have any questions, visit the Apple Developer Forums
Apple Developer Technical Support