diff --git a/modules/ppcp-button/src/Assets/SmartButton.php b/modules/ppcp-button/src/Assets/SmartButton.php
index ac4126f5b..e83510873 100644
--- a/modules/ppcp-button/src/Assets/SmartButton.php
+++ b/modules/ppcp-button/src/Assets/SmartButton.php
@@ -728,7 +728,7 @@ class SmartButton implements SmartButtonInterface {
 	private function payerData() {
 
 		$customer = WC()->customer;
-		if ( ! is_user_logged_in() || ! is_a( $customer, \WC_Customer::class ) ) {
+		if ( ! is_user_logged_in() || ! ( $customer instanceof \WC_Customer ) ) {
 			return null;
 		}
 		return $this->payer_factory->from_customer( $customer )->to_array();
@@ -757,7 +757,7 @@ class SmartButton implements SmartButtonInterface {
 		if (
 			$this->environment->current_environment_is( Environment::SANDBOX )
 			&& defined( 'WP_DEBUG' ) && \WP_DEBUG && is_user_logged_in()
-			&& WC()->customer && WC()->customer->get_billing_country()
+			&& WC()->customer instanceof \WC_Customer && WC()->customer->get_billing_country()
 			&& 2 === strlen( WC()->customer->get_billing_country() )
 		) {
 			$params['buyer-country'] = WC()->customer->get_billing_country();
diff --git a/modules/ppcp-button/src/Endpoint/CreateOrderEndpoint.php b/modules/ppcp-button/src/Endpoint/CreateOrderEndpoint.php
index d8c473bfa..bf6683c63 100644
--- a/modules/ppcp-button/src/Endpoint/CreateOrderEndpoint.php
+++ b/modules/ppcp-button/src/Endpoint/CreateOrderEndpoint.php
@@ -285,7 +285,7 @@ class CreateOrderEndpoint implements EndpointInterface {
 	 * @throws RuntimeException If create order request fails.
 	 */
 	private function create_paypal_order( \WC_Order $wc_order = null ): Order {
-		$needs_shipping          = WC()->cart && WC()->cart->needs_shipping();
+		$needs_shipping          = WC()->cart instanceof \WC_Cart && WC()->cart->needs_shipping();
 		$shipping_address_is_fix = $needs_shipping && 'checkout' === $this->parsed_request_data['context'];
 
 		return $this->api_endpoint->create(
diff --git a/modules/ppcp-subscription/src/SubscriptionModule.php b/modules/ppcp-subscription/src/SubscriptionModule.php
index aca30b3bb..3be24af3d 100644
--- a/modules/ppcp-subscription/src/SubscriptionModule.php
+++ b/modules/ppcp-subscription/src/SubscriptionModule.php
@@ -112,7 +112,7 @@ class SubscriptionModule implements ModuleInterface {
 	 * @return void
 	 */
 	protected function renew( $order, $container ) {
-		if ( ! is_a( $order, \WC_Order::class ) ) {
+		if ( ! ( $order instanceof \WC_Order ) ) {
 			return;
 		}