on Monday that Apple is emailing former MobileMe customers that their free use of 20GB of extra iCloud storage ends this Sunday, Sept. 30. Apple originally that it would extend the transitional arrangement to the end of September, three months beyond the date MobileMe officially closed.

All users of iCloud get their first 5GB of storage for free; MobileMe customers were offered the extra 20GB for free----to help them . MobileMe users previously paid $99 a year for 20GB of service.

Apple is now warning former MobileMe users who exceed the free 5GB limit that unless they start paying for the extra storage, "backups to iCloud will stop, and apps will no longer be able to save documents to iCloud."

Launched in 2008 as a subscription service, Apple's MobileMe offered users online backup for their email, contacts, calendars, and other information stored on their Macs and iOS devices. But iCloud , offering , making the older service mostly redundant. It closed June 30.