I am using below code to get UUID.

```
 -(NSString *)updateUserPhoneDetails{

    NSString *retrieveuuid = [SSKeychain passwordForService:@"com.testUser" account:@"testUser"];    
    NSString *uniqueID;
    if (retrieveuuid == nil) {
        NSString *uuid = [[NSUUID UUID] UUIDString];
        uniqueID=[uuid stringByReplacingOccurrencesOfString:@"-" withString:@""];
        NSLog(@"Create new uuid : %@",uniqueID);
        //Store the password in Keychain
        NSError *error = nil;
        [SSKeychain setPassword:uuid forService:@"com.testUser" account:@"testUser" error:&error];
    }else{
        uniqueID=[retrieveuuid stringByReplacingOccurrencesOfString:@"-" withString:@""];
        NSLog(@"uniqueID  : %@",uniqueID);
    }
    return uniqueID;
}

```

The above code is working fine before iOS 10.0.
I have tested in iPhone 7, iPhone 5s but getting some time different UUID.
I think it should be same at every time when I re-install the same app.
Please help me.