UIDevice uniqueIdentifier deprecated - What to do now?

check this out,

we can use Keychain instead of NSUserDefaults class, to store UUID created by CFUUIDCreate.

with this way we could avoid for UUID recreation with reinstallation, and obtain always same UUID for same application even user uninstall and reinstall again.

UUID will recreated just when device reset by user.

I tried this method with SFHFKeychainUtils and it's works like a charm.

You may want to consider using OpenUDID which is a drop-in replacement for the deprecated UDID.

Basically, to match the UDID, the following features are required:

1. unique or sufficiently unique (a low probability collision is probably very acceptable)
2. persistence across reboots, restores, uninstalls
3. available across apps of different vendors (useful to acquire users via CPI networks) -

OpenUDID fulfills the above and even has a built-in Opt-Out mechanism for later consideration.

Check http://OpenUDID.org it points to the corresponding GitHub. Hope this helps!

As a side note, I would shy away from any MAC address alternative. While the MAC address appears like a tempting and universal solution, be sure that this low hanging fruit is poisoned. The MAC address is very sensitive, and Apple may very well deprecate access to this one before you can even say "SUBMIT THIS APP"... the MAC network address is used to authenticate certain devices on private lans (WLANs) or other virtual private networks (VPNs). .. it's even more sensitive than the former UDID!

I'm sure Apple have annoyed many people with this change. I develop a bookkeeping app for iOS and have an online service to sync changes made on different devices. The service maintains a database of all devices and the changes that need to be propagated to them. Therefore it's important to know which devices are which. I'm keeping track of devices using the UIDevice uniqueIdentifier and for what it's worth, here are my thoughts.

• Generate a UUID and store in user defaults? No good because this does not persist when the user deletes the app. If they install again later the online service should not create a new device record, that would waste resources on the server and give a list of devices containing the same one two or more times. Users would see more than one "Bob's iPhone" listed if they re-installed the app.

• Generate a UUID and store in the keychain? This was my plan, since it persists even when the app is uninstalled. But when restoring an iTunes backup to a new iOS device, the keychain is transferred if the backup is encrypted. This could lead to two devices containing the same device id if the old and new devices are both in service. These should be listed as two devices in the online service, even if the device name is the same.

• Generate a hash the MAC address and bundle id? This looks like the best solution for what I need. By hashing with the bundle id, the generated device id is not going to enable the device to be tracked across apps and I get a unique ID for the app+device combination.

It's interesting to note that Apple's own documentation refers to validating Mac App Store receipts by computing a hash of the system MAC address plus the bundle id and version. So this seems allowable by policy, whether it passes through app review I don't yet know.

+ (NSString *) getUniqueUUID {
    NSError * error;
    NSString * uuid = [KeychainUtils getPasswordForUsername:kBuyassUser andServiceName:kIdOgBetilngService error:&error];
    if (error) {
    NSLog(@"Error geting unique UUID for this device! %@", [error localizedDescription]);
    return nil;
    }
    if (!uuid) {
        DLog(@"No UUID found. Creating a new one.");
        uuid = [IDManager GetUUID];
        uuid = [Util md5String:uuid];
        [KeychainUtils storeUsername:USER_NAME andPassword:uuid forServiceName:SERVICE_NAME updateExisting:YES error:&error];
        if (error) {
            NSLog(@"Error getting unique UUID for this device! %@", [error localizedDescription]);
            return nil;
        }
    }
    return uuid;
}

We can use identifierForVendor for ios7,

-(NSString*)uniqueIDForDevice
{
    NSString* uniqueIdentifier = nil;
    if( [UIDevice instancesRespondToSelector:@selector(identifierForVendor)] ) { // >=iOS 7
        uniqueIdentifier = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
    } else { //<=iOS6, Use UDID of Device       
            CFUUIDRef uuid = CFUUIDCreate(NULL);
            //uniqueIdentifier = ( NSString*)CFUUIDCreateString(NULL, uuid);- for non- ARC
            uniqueIdentifier = ( NSString*)CFBridgingRelease(CFUUIDCreateString(NULL, uuid));// for ARC
            CFRelease(uuid);
         }
    }
return uniqueIdentifier;
}

--Important Note ---

UDID and identifierForVendor are different:---

1.) On uninstalling  and reinstalling the app identifierForVendor will change.

2.) The value of identifierForVendor remains the same for all the apps installed from the same vendor on the device.

3.) The value of identifierForVendor also changes for all the apps if any of the app (from same vendor) is reinstalled.