Apple’s preparations for the launch of iCloud and iOS 5 this Fall will see the Cupertino company reset iCloud backup data on Thursday, September 22 — which will mean any backups made before this date will no longer be accessible.
According to a posting on the Apple Developer boards, the company will delete all iCloud Backup data on September 22, and backing up to the service will be unavailable for a period of time on that day:
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.
It’s worth keeping in mind, then, that any backups you make before Thursday will not be available after the reset. We recommend making a good, old-fashioned iTunes backup just in case anything happens to your device before you get the chance to backup to iCloud again. And trust us, these things have a knack of happening at the worst possible times, so it’s better to be safe than sorry.