[iOS]iOS7以降のModalView呼び出しと解放

float version = [[[UIDevice currentDevice] systemVersion] floatValue];
if (version >= 7.0)  {
    //iOS7以降
    //呼び出し
    [self presentViewController:vc animated:YES completion:nil];
    //解放
    [self dismissViewControllerAnimated:YES completion:nil];
} else {
    //iOS6以前
    //呼び出し
    [self presentViewController:vc animated:YES];
    //解放
    [self.parentViewController dismissModalViewControllerAnimated:YES];
}