NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];

    if ( ![userDefaults valueForKey:@"version"] )
    {
            // CALL your Function;

            // Adding version number to NSUserDefaults for first version:
          [userDefaults setFloat:[[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"] floatValue] forKey:@"version"];    
    }


    if ([[NSUserDefaults standardUserDefaults] floatForKey:@"version"] == [[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"] floatValue] )
    {
    /// Same Version so dont run the function
    }
    else
    {
       // Call Your Function;

       // Update version number to NSUserDefaults for other versions:
         [userDefaults setFloat:[[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"] floatValue] forKey:@"version"];
    }