iOS7 app backward compatible with iOS5 regarding unique identifier

Question

My app is compatible with iOS5 and iOS6. Until now I had no problem using:

NSString DeviceID = [[UIDevice currentDevice] uniqueIdentifier];

Answer 1

Why just not to use CFUUIDRef and be independent with iOS verion?

CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);

self.uuidString = (NSString *)CFUUIDCreateString(NULL,uuidRef);

CFRelease(uuidRef);

And of course remember calculated uuidString in the Keychain(in case of application removal)?

Here is written how to use keychain

Answer 2

As hard replacement of static macro, you can try dynamic if statement to check it.

UIDevice has property named 'systemVersion' and you can check this.

Answer 3

The best and recommend option by Apple is:

 NSString *adId = [[[ASIdentifierManager sharedManager] advertisingIdentifier] UUIDString];

Use it for every device above 5.0.

For 5.0 you have to use uniqueIdentifier. The best to check if it's available is:

if (!NSClassFromString(@"ASIdentifierManager"))

Combining that will give you:

- (NSString *) advertisingIdentifier
{
    if (!NSClassFromString(@"ASIdentifierManager")) {
        SEL selector = NSSelectorFromString(@"uniqueIdentifier");
        if ([[UIDevice currentDevice] respondsToSelector:selector]) {
            return [[UIDevice currentDevice] performSelector:selector];
        }
        //or get macaddress here http://iosdevelopertips.com/device/determine-mac-address.html
    }
    return [[[ASIdentifierManager sharedManager] advertisingIdentifier] UUIDString];
}