You can check the creation date of your documents folder. If it's prior to your 1.1 version release than it's an update.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSDictionary* fileAttribs = [[NSFileManager defaultManager] attributesOfItemAtPath:documentsDirectory error:nil];
NSDate *result = [fileAttribs objectForKey:NSFileCreationDate];
NSLog(@"%@",result);
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