I read Apples doc and I got below information, NSMetadataUbiquitousItemIsDownloadedKey The value is an NSNumber object that contains a Boolean indicating whether the current version of the item has been downloaded and is available locally.
so now query is that suppose I have two devices iPhoneA and iPhoneB and there is one common file named file1, now suppose right now I have iCloud version of file1 on both devices so NSMetadataUbiquitousItemIsDownloadedKey will be 1 for file1 on both devices.
then I modify file1 on iPhoneB and have uploaded it on iCloud, so now when I run application on iPhoneA and start iCloud sync what will be value of NSMetadataUbiquitousItemIsDownloadedKey for file1.
NSMetadataUbiquitousItemIsDownloadedKey value will be 1 for this case.