@mhcwebdesign It is correct?

Looks good to me.

Having said that, I don't think it will work, because of these lines:

			if ($this->config->get('payment_pp_express_test')) {
				$api_url = 'https://api-3t.sandbox.paypal.com/nvp';
				$api_username = $this->config->get('payment_pp_express_sandbox_username');
				$api_password = $this->config->get('payment_pp_express_sandbox_password');
				$api_signature = $this->config->get('payment_pp_express_sandbox_signature');
			} else {
				$api_url = 'https://api-3t.paypal.com/nvp';
				$api_username = $this->config->get('payment_pp_express_username');
				$api_password = $this->config->get('payment_pp_express_password');
				$api_signature = $this->config->get('payment_pp_express_signature');
			}

These config values don't exist anymore, we'd have to add a simple admin/controller/extension/payment/pp_express-recurring.php where it can be enabled and configured.

But doesn't the PayPal Integration support recurring payments, too?

I think Paypal Express supported recurring payments.

I think Paypal Express supported recurring payments.

It probably did. I was just wondering whether the new PayPal Checkout Integration extension can support recurring payments, too.

This just needs removing. There is no PayPal express extension anymore to set the payment_pp_express_xxx configuration settings. So this will just do nothing.