diff --git a/.psalm/wcs.php b/.psalm/wcs.php
index a35088c88..cc33e0103 100644
--- a/.psalm/wcs.php
+++ b/.psalm/wcs.php
@@ -2093,3 +2093,17 @@ function wcs_order_contains_product($order, $product)
  * @return string Page ID. Empty string if resource not found.
  */
 function wc_get_page_screen_id( $for ) {}
+
+/**
+ * Subscription Product Variation Class
+ *
+ * The subscription product variation class extends the WC_Product_Variation product class
+ * to create subscription product variations.
+ *
+ * @class    WC_Product_Subscription
+ * @package  WooCommerce Subscriptions
+ * @category Class
+ * @since    1.0.0 - Migrated from WooCommerce Subscriptions v1.3
+ *
+ */
+class WC_Product_Subscription_Variation extends WC_Product_Variation {}
diff --git a/modules/ppcp-subscription/src/Helper/SubscriptionHelper.php b/modules/ppcp-subscription/src/Helper/SubscriptionHelper.php
index 619fbc658..635e66cc1 100644
--- a/modules/ppcp-subscription/src/Helper/SubscriptionHelper.php
+++ b/modules/ppcp-subscription/src/Helper/SubscriptionHelper.php
@@ -219,6 +219,11 @@ class SubscriptionHelper {
 		return '';
 	}
 
+	/**
+	 * Returns variations for variable PayPal subscription product.
+	 *
+	 * @return array
+	 */
 	public function variable_paypal_subscription_variations(): array {
 		$variations = array();
 		if ( ! $this->current_product_is_subscription() ) {
@@ -232,16 +237,16 @@ class SubscriptionHelper {
 		}
 
 		$variation_ids = $product->get_children();
-		foreach ($variation_ids as $id) {
-			$product = wc_get_product($id);
-			if(! is_a($product, WC_Product_Subscription_Variation::class )) {
+		foreach ( $variation_ids as $id ) {
+			$product = wc_get_product( $id );
+			if ( ! is_a( $product, WC_Product_Subscription_Variation::class ) ) {
 				continue;
 			}
 
-			$subscription_plan = $product->get_meta('ppcp_subscription_plan') ?? '';
-			$variations[] = array(
-				'id' => $product->get_id(),
-				'attributes' => $product->get_attributes(),
+			$subscription_plan = $product->get_meta( 'ppcp_subscription_plan' ) ?? array();
+			$variations[]      = array(
+				'id'                => $product->get_id(),
+				'attributes'        => $product->get_attributes(),
 				'subscription_plan' => $subscription_plan['id'] ?? '',
 			);
 		}
diff --git a/modules/ppcp-subscription/src/SubscriptionModule.php b/modules/ppcp-subscription/src/SubscriptionModule.php
index d2077db06..5fe6f1dc1 100644
--- a/modules/ppcp-subscription/src/SubscriptionModule.php
+++ b/modules/ppcp-subscription/src/SubscriptionModule.php
@@ -12,6 +12,7 @@ namespace WooCommerce\PayPalCommerce\Subscription;
 use Exception;
 use WC_Product;
 use WC_Product_Subscription_Variation;
+use WC_Product_Variable;
 use WC_Product_Variable_Subscription;
 use WC_Subscriptions_Product;
 use WooCommerce\PayPalCommerce\ApiClient\Endpoint\BillingSubscriptions;
@@ -195,9 +196,15 @@ class SubscriptionModule implements ModuleInterface {
 
 				$products = array( $this->set_product_config( $product ) );
 				if ( $product->get_type() === 'variable-subscription' ) {
-					$products             = array();
+					$products = array();
+					assert( $product instanceof WC_Product_Variable );
 					$available_variations = $product->get_available_variations();
 					foreach ( $available_variations as $variation ) {
+						/**
+						 * The method is defined in WooCommerce.
+						 *
+						 * @psalm-suppress UndefinedMethod
+						 */
 						$variation  = wc_get_product_object( 'variation', $variation['variation_id'] );
 						$products[] = $this->set_product_config( $variation );
 					}
@@ -472,9 +479,18 @@ class SubscriptionModule implements ModuleInterface {
 
 		add_action(
 			'woocommerce_save_product_variation',
+			/**
+			 * Param types removed to avoid third-party issues.
+			 *
+			 * @psalm-suppress MissingClosureParamType
+			 */
 			function( $variation_id ) use ( $c ) {
 				$wcsnonce_save_variations = wc_clean( wp_unslash( $_POST['_wcsnonce_save_variations'] ?? '' ) );
-				if ( ! WC_Subscriptions_Product::is_subscription( $variation_id ) || empty( $wcsnonce_save_variations ) || ! wp_verify_nonce( $wcsnonce_save_variations, 'wcs_subscription_variations' ) ) {
+				if (
+					! WC_Subscriptions_Product::is_subscription( $variation_id )
+					|| ! is_string( $wcsnonce_save_variations )
+					|| ! wp_verify_nonce( $wcsnonce_save_variations, 'wcs_subscription_variations' )
+				) {
 					return;
 				}
 
@@ -808,6 +824,11 @@ class SubscriptionModule implements ModuleInterface {
 
 		add_action(
 			'woocommerce_variation_options_pricing',
+			/**
+			 * Param types removed to avoid third-party issues.
+			 *
+			 * @psalm-suppress MissingClosureParamType
+			 */
 			function( $loop, $variation_data, $variation ) use ( $c ) {
 				$settings = $c->get( 'wcgateway.settings' );
 				assert( $settings instanceof Settings );