A new posting on the Apple Developer Boards suggests that Apple will be completely resetting iCloud backup data on Thursday, September 22nd. 9to5Mac suggests that the reset is being performed to prepare for Apple’s release of the iOS 5 Gold Master, which many expect to be released on September 23rd, around the same time as the reset.
The iOS 5 Gold Master will be Apple’s last iOS 5 release before the final retail version, and will mark the completion of iOS 5. The reset does not include mail, contact, calendar, reminder or bookmark data, but instead will simply be a reset of device backups on iCloud. From the Apple Developer Forums:
On Thursday, September 22, the iCloud Backup data will be reset. Backing up to iCloud or restoring from an iCloud backup will be unavailable from 9 AM PDT – 5 PM PDT. If you attempt a backup or restore during this time, you will receive an alert that the backup or restore was not successful. After this reset, you will be unable to restore from any backup created prior to September 22. A full backup will happen automatically the next time your device backs up to iCloud.
Apple has been testing iOS 5 with developers since June, and has so far provided 7 betas of the new platform. iOS 5 is expected to launch this fall, with many expecting it in early October near the anticipated release of the iPhone 5.