diff --git a/includes/gateways/bacs/class-wc-gateway-bacs.php b/includes/gateways/bacs/class-wc-gateway-bacs.php
index 1e155df98f2..dabc097e469 100644
--- a/includes/gateways/bacs/class-wc-gateway-bacs.php
+++ b/includes/gateways/bacs/class-wc-gateway-bacs.php
@@ -1,7 +1,12 @@
 <?php
+/**
+ * Class WC_Gateway_BACS file.
+ *
+ * @package WooCommerce\Gateways
+ */
 
 if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly
+	exit; // Exit if accessed directly.
 }
 
 /**
@@ -13,11 +18,14 @@ if ( ! defined( 'ABSPATH' ) ) {
  * @extends     WC_Payment_Gateway
  * @version     2.1.0
  * @package     WooCommerce/Classes/Payment
- * @author      WooThemes
  */
 class WC_Gateway_BACS extends WC_Payment_Gateway {
 
-	/** @var array Array of locales */
+	/**
+	 * Array of locales
+	 *
+	 * @var array
+	 */
 	public $locale;
 
 	/**
@@ -35,13 +43,14 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 		$this->init_form_fields();
 		$this->init_settings();
 
-		// Define user set variables
+		// Define user set variables.
 		$this->title        = $this->get_option( 'title' );
 		$this->description  = $this->get_option( 'description' );
 		$this->instructions = $this->get_option( 'instructions' );
 
-		// BACS account fields shown on the thanks page and in emails
-		$this->account_details = get_option( 'woocommerce_bacs_accounts',
+		// BACS account fields shown on the thanks page and in emails.
+		$this->account_details = get_option(
+			'woocommerce_bacs_accounts',
 			array(
 				array(
 					'account_name'   => $this->get_option( 'account_name' ),
@@ -54,12 +63,12 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 			)
 		);
 
-		// Actions
+		// Actions.
 		add_action( 'woocommerce_update_options_payment_gateways_' . $this->id, array( $this, 'process_admin_options' ) );
 		add_action( 'woocommerce_update_options_payment_gateways_' . $this->id, array( $this, 'save_account_details' ) );
 		add_action( 'woocommerce_thankyou_bacs', array( $this, 'thankyou_page' ) );
 
-		// Customer Emails
+		// Customer Emails.
 		add_action( 'woocommerce_email_before_order_table', array( $this, 'email_instructions' ), 10, 3 );
 	}
 
@@ -69,27 +78,27 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 	public function init_form_fields() {
 
 		$this->form_fields = array(
-			'enabled' => array(
+			'enabled'         => array(
 				'title'   => __( 'Enable/Disable', 'woocommerce' ),
 				'type'    => 'checkbox',
 				'label'   => __( 'Enable bank transfer', 'woocommerce' ),
 				'default' => 'no',
 			),
-			'title' => array(
+			'title'           => array(
 				'title'       => __( 'Title', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'This controls the title which the user sees during checkout.', 'woocommerce' ),
 				'default'     => __( 'Direct bank transfer', 'woocommerce' ),
 				'desc_tip'    => true,
 			),
-			'description' => array(
+			'description'     => array(
 				'title'       => __( 'Description', 'woocommerce' ),
 				'type'        => 'textarea',
 				'description' => __( 'Payment method description that the customer will see on your checkout.', 'woocommerce' ),
 				'default'     => __( 'Make your payment directly into our bank account. Please use your Order ID as the payment reference. Your order will not be shipped until the funds have cleared in our account.', 'woocommerce' ),
 				'desc_tip'    => true,
 			),
-			'instructions' => array(
+			'instructions'    => array(
 				'title'       => __( 'Instructions', 'woocommerce' ),
 				'type'        => 'textarea',
 				'description' => __( 'Instructions that will be added to the thank you page and emails.', 'woocommerce' ),
@@ -97,7 +106,7 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 				'desc_tip'    => true,
 			),
 			'account_details' => array(
-				'type'        => 'account_details',
+				'type' => 'account_details',
 			),
 		);
 
@@ -112,27 +121,27 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 
 		ob_start();
 
-		$country 	= WC()->countries->get_base_country();
-		$locale		= $this->get_country_locale();
+		$country = WC()->countries->get_base_country();
+		$locale  = $this->get_country_locale();
 
-		// Get sortcode label in the $locale array and use appropriate one
+		// Get sortcode label in the $locale array and use appropriate one.
 		$sortcode = isset( $locale[ $country ]['sortcode']['label'] ) ? $locale[ $country ]['sortcode']['label'] : __( 'Sort code', 'woocommerce' );
 
 		?>
 		<tr valign="top">
-			<th scope="row" class="titledesc"><?php _e( 'Account details', 'woocommerce' ); ?>:</th>
+			<th scope="row" class="titledesc"><?php esc_html_e( 'Account details:', 'woocommerce' ); ?></th>
 			<td class="forminp" id="bacs_accounts">
 				<div class="wc_input_table_wrapper">
 					<table class="widefat wc_input_table sortable" cellspacing="0">
 						<thead>
 							<tr>
 								<th class="sort">&nbsp;</th>
-								<th><?php _e( 'Account name', 'woocommerce' ); ?></th>
-								<th><?php _e( 'Account number', 'woocommerce' ); ?></th>
-								<th><?php _e( 'Bank name', 'woocommerce' ); ?></th>
-								<th><?php echo $sortcode; ?></th>
-								<th><?php _e( 'IBAN', 'woocommerce' ); ?></th>
-								<th><?php _e( 'BIC / Swift', 'woocommerce' ); ?></th>
+								<th><?php esc_html_e( 'Account name', 'woocommerce' ); ?></th>
+								<th><?php esc_html_e( 'Account number', 'woocommerce' ); ?></th>
+								<th><?php esc_html_e( 'Bank name', 'woocommerce' ); ?></th>
+								<th><?php echo esc_html( $sortcode ); ?></th>
+								<th><?php esc_html_e( 'IBAN', 'woocommerce' ); ?></th>
+								<th><?php esc_html_e( 'BIC / Swift', 'woocommerce' ); ?></th>
 							</tr>
 						</thead>
 						<tbody class="accounts">
@@ -144,12 +153,12 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 
 									echo '<tr class="account">
 										<td class="sort"></td>
-										<td><input type="text" value="' . esc_attr( wp_unslash( $account['account_name'] ) ) . '" name="bacs_account_name[' . $i . ']" /></td>
-										<td><input type="text" value="' . esc_attr( $account['account_number'] ) . '" name="bacs_account_number[' . $i . ']" /></td>
-										<td><input type="text" value="' . esc_attr( wp_unslash( $account['bank_name'] ) ) . '" name="bacs_bank_name[' . $i . ']" /></td>
-										<td><input type="text" value="' . esc_attr( $account['sort_code'] ) . '" name="bacs_sort_code[' . $i . ']" /></td>
-										<td><input type="text" value="' . esc_attr( $account['iban'] ) . '" name="bacs_iban[' . $i . ']" /></td>
-										<td><input type="text" value="' . esc_attr( $account['bic'] ) . '" name="bacs_bic[' . $i . ']" /></td>
+										<td><input type="text" value="' . esc_attr( wp_unslash( $account['account_name'] ) ) . '" name="bacs_account_name[' . esc_attr( $i ) . ']" /></td>
+										<td><input type="text" value="' . esc_attr( $account['account_number'] ) . '" name="bacs_account_number[' . esc_attr( $i ) . ']" /></td>
+										<td><input type="text" value="' . esc_attr( wp_unslash( $account['bank_name'] ) ) . '" name="bacs_bank_name[' . esc_attr( $i ) . ']" /></td>
+										<td><input type="text" value="' . esc_attr( $account['sort_code'] ) . '" name="bacs_sort_code[' . esc_attr( $i ) . ']" /></td>
+										<td><input type="text" value="' . esc_attr( $account['iban'] ) . '" name="bacs_iban[' . esc_attr( $i ) . ']" /></td>
+										<td><input type="text" value="' . esc_attr( $account['bic'] ) . '" name="bacs_bic[' . esc_attr( $i ) . ']" /></td>
 									</tr>';
 								}
 							}
@@ -157,7 +166,7 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 						</tbody>
 						<tfoot>
 							<tr>
-								<th colspan="7"><a href="#" class="add button"><?php _e( '+ Add account', 'woocommerce' ); ?></a> <a href="#" class="remove_rows button"><?php _e( 'Remove selected account(s)', 'woocommerce' ); ?></a></th>
+								<th colspan="7"><a href="#" class="add button"><?php esc_html_e( '+ Add account', 'woocommerce' ); ?></a> <a href="#" class="remove_rows button"><?php esc_html_e( 'Remove selected account(s)', 'woocommerce' ); ?></a></th>
 							</tr>
 						</tfoot>
 					</table>
@@ -196,14 +205,16 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 
 		$accounts = array();
 
-		if ( isset( $_POST['bacs_account_name'] ) ) {
+		// phpcs:disable WordPress.CSRF.NonceVerification.NoNonceVerification -- Nonce verification already handled in WC_Admin_Settings::save()
+		if ( isset( $_POST['bacs_account_name'] ) && isset( $_POST['bacs_account_number'] ) && isset( $_POST['bacs_bank_name'] )
+			 && isset( $_POST['bacs_sort_code'] ) && isset( $_POST['bacs_iban'] ) && isset( $_POST['bacs_bic'] ) ) {
 
-			$account_names   = array_map( 'wc_clean', $_POST['bacs_account_name'] );
-			$account_numbers = array_map( 'wc_clean', $_POST['bacs_account_number'] );
-			$bank_names      = array_map( 'wc_clean', $_POST['bacs_bank_name'] );
-			$sort_codes      = array_map( 'wc_clean', $_POST['bacs_sort_code'] );
-			$ibans           = array_map( 'wc_clean', $_POST['bacs_iban'] );
-			$bics            = array_map( 'wc_clean', $_POST['bacs_bic'] );
+			$account_names   = wc_clean( wp_unslash( $_POST['bacs_account_name'] ) );
+			$account_numbers = wc_clean( wp_unslash( $_POST['bacs_account_number'] ) );
+			$bank_names      = wc_clean( wp_unslash( $_POST['bacs_bank_name'] ) );
+			$sort_codes      = wc_clean( wp_unslash( $_POST['bacs_sort_code'] ) );
+			$ibans           = wc_clean( wp_unslash( $_POST['bacs_iban'] ) );
+			$bics            = wc_clean( wp_unslash( $_POST['bacs_bic'] ) );
 
 			foreach ( $account_names as $i => $name ) {
 				if ( ! isset( $account_names[ $i ] ) ) {
@@ -220,20 +231,20 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 				);
 			}
 		}
+		// phpcs:enable
 
 		update_option( 'woocommerce_bacs_accounts', $accounts );
-
 	}
 
 	/**
 	 * Output for the order received page.
 	 *
-	 * @param int $order_id
+	 * @param int $order_id Order ID.
 	 */
 	public function thankyou_page( $order_id ) {
 
 		if ( $this->instructions ) {
-			echo wpautop( wptexturize( wp_kses_post( $this->instructions ) ) );
+			echo wp_kses_post( wpautop( wptexturize( wp_kses_post( $this->instructions ) ) ) );
 		}
 		$this->bank_details( $order_id );
 
@@ -242,15 +253,15 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 	/**
 	 * Add content to the WC emails.
 	 *
-	 * @param WC_Order $order
-	 * @param bool $sent_to_admin
-	 * @param bool $plain_text
+	 * @param WC_Order $order Order object.
+	 * @param bool     $sent_to_admin Sent to admin.
+	 * @param bool     $plain_text Email format: plain text or HTML.
 	 */
 	public function email_instructions( $order, $sent_to_admin, $plain_text = false ) {
 
 		if ( ! $sent_to_admin && 'bacs' === $order->get_payment_method() && $order->has_status( 'on-hold' ) ) {
 			if ( $this->instructions ) {
-				echo wpautop( wptexturize( $this->instructions ) ) . PHP_EOL;
+				echo wp_kses_post( wpautop( wptexturize( $this->instructions ) ) . PHP_EOL );
 			}
 			$this->bank_details( $order->get_id() );
 		}
@@ -260,7 +271,7 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 	/**
 	 * Get bank details and place into a list format.
 	 *
-	 * @param int $order_id
+	 * @param int $order_id Order ID.
 	 */
 	private function bank_details( $order_id = '' ) {
 
@@ -268,14 +279,14 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 			return;
 		}
 
-		// Get order and store in $order
-		$order 		= wc_get_order( $order_id );
+		// Get order and store in $order.
+		$order = wc_get_order( $order_id );
 
-		// Get the order country and country $locale
-		$country 	= $order->get_billing_country();
-		$locale		= $this->get_country_locale();
+		// Get the order country and country $locale.
+		$country = $order->get_billing_country();
+		$locale  = $this->get_country_locale();
 
-		// Get sortcode label in the $locale array and use appropriate one
+		// Get sortcode label in the $locale array and use appropriate one.
 		$sortcode = isset( $locale[ $country ]['sortcode']['label'] ) ? $locale[ $country ]['sortcode']['label'] : __( 'Sort code', 'woocommerce' );
 
 		$bacs_accounts = apply_filters( 'woocommerce_bacs_accounts', $this->account_details );
@@ -293,29 +304,31 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 
 				$account_html .= '<ul class="wc-bacs-bank-details order_details bacs_details">' . PHP_EOL;
 
-				// BACS account fields shown on the thanks page and in emails
-				$account_fields = apply_filters( 'woocommerce_bacs_account_fields', array(
-					'bank_name' => array(
-						'label' => __( 'Bank', 'woocommerce' ),
-						'value' => $bacs_account->bank_name,
-					),
-					'account_number' => array(
-						'label' => __( 'Account number', 'woocommerce' ),
-						'value' => $bacs_account->account_number,
-					),
-					'sort_code'     => array(
-						'label' => $sortcode,
-						'value' => $bacs_account->sort_code,
-					),
-					'iban'          => array(
-						'label' => __( 'IBAN', 'woocommerce' ),
-						'value' => $bacs_account->iban,
-					),
-					'bic'           => array(
-						'label' => __( 'BIC', 'woocommerce' ),
-						'value' => $bacs_account->bic,
-					),
-				), $order_id );
+				// BACS account fields shown on the thanks page and in emails.
+				$account_fields = apply_filters(
+					'woocommerce_bacs_account_fields', array(
+						'bank_name'      => array(
+							'label' => __( 'Bank', 'woocommerce' ),
+							'value' => $bacs_account->bank_name,
+						),
+						'account_number' => array(
+							'label' => __( 'Account number', 'woocommerce' ),
+							'value' => $bacs_account->account_number,
+						),
+						'sort_code'      => array(
+							'label' => $sortcode,
+							'value' => $bacs_account->sort_code,
+						),
+						'iban'           => array(
+							'label' => __( 'IBAN', 'woocommerce' ),
+							'value' => $bacs_account->iban,
+						),
+						'bic'            => array(
+							'label' => __( 'BIC', 'woocommerce' ),
+							'value' => $bacs_account->bic,
+						),
+					), $order_id
+				);
 
 				foreach ( $account_fields as $field_key => $field ) {
 					if ( ! empty( $field['value'] ) ) {
@@ -328,7 +341,7 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 			}
 
 			if ( $has_details ) {
-				echo '<section class="woocommerce-bacs-bank-details"><h2 class="wc-bacs-bank-details-heading">' . __( 'Our bank details', 'woocommerce' ) . '</h2>' . PHP_EOL . $account_html . '</section>';
+				echo '<section class="woocommerce-bacs-bank-details"><h2 class="wc-bacs-bank-details-heading">' . esc_html__( 'Our bank details', 'woocommerce' ) . '</h2>' . wp_kses_post( PHP_EOL . $account_html ) . '</section>';
 			}
 		}
 
@@ -337,7 +350,7 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 	/**
 	 * Process the payment and return the result.
 	 *
-	 * @param int $order_id
+	 * @param int $order_id Order ID.
 	 * @return array
 	 */
 	public function process_payment( $order_id ) {
@@ -345,22 +358,22 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 		$order = wc_get_order( $order_id );
 
 		if ( $order->get_total() > 0 ) {
-			// Mark as on-hold (we're awaiting the payment)
+			// Mark as on-hold (we're awaiting the payment).
 			$order->update_status( 'on-hold', __( 'Awaiting BACS payment', 'woocommerce' ) );
 		} else {
 			$order->payment_complete();
 		}
 
-		// Reduce stock levels
+		// Reduce stock levels.
 		wc_reduce_stock_levels( $order_id );
 
-		// Remove cart
+		// Remove cart.
 		WC()->cart->empty_cart();
 
-		// Return thankyou redirect
+		// Return thankyou redirect.
 		return array(
-			'result'    => 'success',
-			'redirect'  => $this->get_return_url( $order ),
+			'result'   => 'success',
+			'redirect' => $this->get_return_url( $order ),
 		);
 
 	}
@@ -374,49 +387,51 @@ class WC_Gateway_BACS extends WC_Payment_Gateway {
 
 		if ( empty( $this->locale ) ) {
 
-			// Locale information to be used - only those that are not 'Sort Code'
-			$this->locale = apply_filters( 'woocommerce_get_bacs_locale', array(
-				'AU' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'BSB', 'woocommerce' ),
+			// Locale information to be used - only those that are not 'Sort Code'.
+			$this->locale = apply_filters(
+				'woocommerce_get_bacs_locale', array(
+					'AU' => array(
+						'sortcode' => array(
+							'label' => __( 'BSB', 'woocommerce' ),
+						),
 					),
-				),
-				'CA' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'Bank transit number', 'woocommerce' ),
+					'CA' => array(
+						'sortcode' => array(
+							'label' => __( 'Bank transit number', 'woocommerce' ),
+						),
 					),
-				),
-				'IN' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'IFSC', 'woocommerce' ),
+					'IN' => array(
+						'sortcode' => array(
+							'label' => __( 'IFSC', 'woocommerce' ),
+						),
 					),
-				),
-				'IT' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'Branch sort', 'woocommerce' ),
+					'IT' => array(
+						'sortcode' => array(
+							'label' => __( 'Branch sort', 'woocommerce' ),
+						),
 					),
-				),
-				'NZ' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'Bank code', 'woocommerce' ),
+					'NZ' => array(
+						'sortcode' => array(
+							'label' => __( 'Bank code', 'woocommerce' ),
+						),
 					),
-				),
-				'SE' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'Bank code', 'woocommerce' ),
+					'SE' => array(
+						'sortcode' => array(
+							'label' => __( 'Bank code', 'woocommerce' ),
+						),
 					),
-				),
-				'US' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'Routing number', 'woocommerce' ),
+					'US' => array(
+						'sortcode' => array(
+							'label' => __( 'Routing number', 'woocommerce' ),
+						),
 					),
-				),
-				'ZA' => array(
-					'sortcode'	=> array(
-						'label'		=> __( 'Branch code', 'woocommerce' ),
+					'ZA' => array(
+						'sortcode' => array(
+							'label' => __( 'Branch code', 'woocommerce' ),
+						),
 					),
-				),
-			) );
+				)
+			);
 
 		}
 
diff --git a/includes/gateways/cheque/class-wc-gateway-cheque.php b/includes/gateways/cheque/class-wc-gateway-cheque.php
index 3a0c90d5781..837718ad9c6 100644
--- a/includes/gateways/cheque/class-wc-gateway-cheque.php
+++ b/includes/gateways/cheque/class-wc-gateway-cheque.php
@@ -1,7 +1,12 @@
 <?php
+/**
+ * Class WC_Gateway_Cheque file.
+ *
+ * @package WooCommerce\Gateways
+ */
 
 if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly
+	exit; // Exit if accessed directly.
 }
 
 /**
@@ -9,11 +14,10 @@ if ( ! defined( 'ABSPATH' ) ) {
  *
  * Provides a Cheque Payment Gateway, mainly for testing purposes.
  *
- * @class 		WC_Gateway_Cheque
- * @extends		WC_Payment_Gateway
- * @version		2.1.0
- * @package		WooCommerce/Classes/Payment
- * @author 		WooThemes
+ * @class       WC_Gateway_Cheque
+ * @extends     WC_Payment_Gateway
+ * @version     2.1.0
+ * @package     WooCommerce/Classes/Payment
  */
 class WC_Gateway_Cheque extends WC_Payment_Gateway {
 
@@ -31,16 +35,16 @@ class WC_Gateway_Cheque extends WC_Payment_Gateway {
 		$this->init_form_fields();
 		$this->init_settings();
 
-		// Define user set variables
+		// Define user set variables.
 		$this->title        = $this->get_option( 'title' );
 		$this->description  = $this->get_option( 'description' );
 		$this->instructions = $this->get_option( 'instructions' );
 
-		// Actions
+		// Actions.
 		add_action( 'woocommerce_update_options_payment_gateways_' . $this->id, array( $this, 'process_admin_options' ) );
 		add_action( 'woocommerce_thankyou_cheque', array( $this, 'thankyou_page' ) );
 
-		// Customer Emails
+		// Customer Emails.
 		add_action( 'woocommerce_email_before_order_table', array( $this, 'email_instructions' ), 10, 3 );
 	}
 
@@ -50,20 +54,20 @@ class WC_Gateway_Cheque extends WC_Payment_Gateway {
 	public function init_form_fields() {
 
 		$this->form_fields = array(
-			'enabled' => array(
+			'enabled'      => array(
 				'title'   => __( 'Enable/Disable', 'woocommerce' ),
 				'type'    => 'checkbox',
 				'label'   => __( 'Enable check payments', 'woocommerce' ),
 				'default' => 'no',
 			),
-			'title' => array(
+			'title'        => array(
 				'title'       => __( 'Title', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'This controls the title which the user sees during checkout.', 'woocommerce' ),
 				'default'     => _x( 'Check payments', 'Check payment method', 'woocommerce' ),
 				'desc_tip'    => true,
 			),
-			'description' => array(
+			'description'  => array(
 				'title'       => __( 'Description', 'woocommerce' ),
 				'type'        => 'textarea',
 				'description' => __( 'Payment method description that the customer will see on your checkout.', 'woocommerce' ),
@@ -85,7 +89,7 @@ class WC_Gateway_Cheque extends WC_Payment_Gateway {
 	 */
 	public function thankyou_page() {
 		if ( $this->instructions ) {
-			echo wpautop( wptexturize( $this->instructions ) );
+			echo wp_kses_post( wpautop( wptexturize( $this->instructions ) ) );
 		}
 	}
 
@@ -93,20 +97,20 @@ class WC_Gateway_Cheque extends WC_Payment_Gateway {
 	 * Add content to the WC emails.
 	 *
 	 * @access public
-	 * @param WC_Order $order
-	 * @param bool $sent_to_admin
-	 * @param bool $plain_text
+	 * @param WC_Order $order Order object.
+	 * @param bool     $sent_to_admin Sent to admin.
+	 * @param bool     $plain_text Email format: plain text or HTML.
 	 */
 	public function email_instructions( $order, $sent_to_admin, $plain_text = false ) {
 		if ( $this->instructions && ! $sent_to_admin && 'cheque' === $order->get_payment_method() && $order->has_status( 'on-hold' ) ) {
-			echo wpautop( wptexturize( $this->instructions ) ) . PHP_EOL;
+			echo wp_kses_post( wpautop( wptexturize( $this->instructions ) ) . PHP_EOL );
 		}
 	}
 
 	/**
 	 * Process the payment and return the result.
 	 *
-	 * @param int $order_id
+	 * @param int $order_id Order ID.
 	 * @return array
 	 */
 	public function process_payment( $order_id ) {
@@ -114,22 +118,22 @@ class WC_Gateway_Cheque extends WC_Payment_Gateway {
 		$order = wc_get_order( $order_id );
 
 		if ( $order->get_total() > 0 ) {
-			// Mark as on-hold (we're awaiting the cheque)
+			// Mark as on-hold (we're awaiting the cheque).
 			$order->update_status( 'on-hold', _x( 'Awaiting check payment', 'Check payment method', 'woocommerce' ) );
 		} else {
 			$order->payment_complete();
 		}
 
-		// Reduce stock levels
+		// Reduce stock levels.
 		wc_reduce_stock_levels( $order_id );
 
-		// Remove cart
+		// Remove cart.
 		WC()->cart->empty_cart();
 
-		// Return thankyou redirect
+		// Return thankyou redirect.
 		return array(
-			'result' 	=> 'success',
-			'redirect'	=> $this->get_return_url( $order ),
+			'result'   => 'success',
+			'redirect' => $this->get_return_url( $order ),
 		);
 	}
 }
diff --git a/includes/gateways/class-wc-payment-gateway-cc.php b/includes/gateways/class-wc-payment-gateway-cc.php
index 608bb34e955..14c8c66f234 100644
--- a/includes/gateways/class-wc-payment-gateway-cc.php
+++ b/includes/gateways/class-wc-payment-gateway-cc.php
@@ -1,4 +1,10 @@
 <?php
+/**
+ * Class WC_Payment_Gateway_CC file.
+ *
+ * @package WooCommerce\Gateways
+ */
+
 if ( ! defined( 'ABSPATH' ) ) {
 	exit;
 }
@@ -7,14 +13,14 @@ if ( ! defined( 'ABSPATH' ) ) {
  * Credit Card Payment Gateway
  *
  * @since       2.6.0
- * @package		WooCommerce/Classes
- * @author 		WooThemes
+ * @package     WooCommerce/Classes
  */
 class WC_Payment_Gateway_CC extends WC_Payment_Gateway {
 
 	/**
 	 * Builds our payment fields area - including tokenization fields for logged
 	 * in users, and the actual payment fields.
+	 *
 	 * @since 2.6.0
 	 */
 	public function payment_fields() {
@@ -34,7 +40,7 @@ class WC_Payment_Gateway_CC extends WC_Payment_Gateway {
 	 * Gateways which support tokenization do not require names - we don't want the data to post to the server.
 	 *
 	 * @since  2.6.0
-	 * @param  string $name
+	 * @param  string $name Field name.
 	 * @return string
 	 */
 	public function field_name( $name ) {
@@ -43,6 +49,7 @@ class WC_Payment_Gateway_CC extends WC_Payment_Gateway {
 
 	/**
 	 * Outputs fields for entering credit card information.
+	 *
 	 * @since 2.6.0
 	 */
 	public function form() {
@@ -76,9 +83,9 @@ class WC_Payment_Gateway_CC extends WC_Payment_Gateway {
 		<fieldset id="wc-<?php echo esc_attr( $this->id ); ?>-cc-form" class='wc-credit-card-form wc-payment-form'>
 			<?php do_action( 'woocommerce_credit_card_form_start', $this->id ); ?>
 			<?php
-				foreach ( $fields as $field ) {
-				echo $field;
-				}
+			foreach ( $fields as $field ) {
+				echo $field; // phpcs:ignore WordPress.XSS.EscapeOutput.OutputNotEscaped
+			}
 			?>
 			<?php do_action( 'woocommerce_credit_card_form_end', $this->id ); ?>
 			<div class="clear"></div>
@@ -86,7 +93,7 @@ class WC_Payment_Gateway_CC extends WC_Payment_Gateway {
 		<?php
 
 		if ( $this->supports( 'credit_card_form_cvc_on_saved_method' ) ) {
-			echo '<fieldset>' . $cvc_field . '</fieldset>';
+			echo '<fieldset>' . $cvc_field . '</fieldset>'; // phpcs:ignore WordPress.XSS.EscapeOutput.OutputNotEscaped
 		}
 	}
 }
diff --git a/includes/gateways/class-wc-payment-gateway-echeck.php b/includes/gateways/class-wc-payment-gateway-echeck.php
index 652fa497fb6..10fea4f88a4 100644
--- a/includes/gateways/class-wc-payment-gateway-echeck.php
+++ b/includes/gateways/class-wc-payment-gateway-echeck.php
@@ -1,20 +1,26 @@
 <?php
+/**
+ * Class WC_Payment_Gateway_eCheck file.
+ *
+ * @package WooCommerce\Gateways
+ */
+
 if ( ! defined( 'ABSPATH' ) ) {
 	exit;
 }
 
 /**
- * eCheck Payment Gateway
+ * Class for eCheck Payment Gateway
  *
  * @since       2.6.0
- * @package		WooCommerce/Classes
- * @author 		WooThemes
+ * @package     WooCommerce/Classes
  */
-class WC_Payment_Gateway_eCheck extends WC_Payment_Gateway {
+class WC_Payment_Gateway_ECheck extends WC_Payment_Gateway {
 
 	/**
 	 * Builds our payment fields area - including tokenization fields for logged
 	 * in users, and the actual payment fields.
+	 *
 	 * @since 2.6.0
 	 */
 	public function payment_fields() {
@@ -30,6 +36,7 @@ class WC_Payment_Gateway_eCheck extends WC_Payment_Gateway {
 
 	/**
 	 * Outputs fields for entering eCheck information.
+	 *
 	 * @since 2.6.0
 	 */
 	public function form() {
@@ -52,12 +59,13 @@ class WC_Payment_Gateway_eCheck extends WC_Payment_Gateway {
 		<fieldset id="<?php echo esc_attr( $this->id ); ?>-cc-form" class='wc-echeck-form wc-payment-form'>
 			<?php do_action( 'woocommerce_echeck_form_start', $this->id ); ?>
 			<?php
-				foreach ( $fields as $field ) {
-					echo $field;
-				}
+			foreach ( $fields as $field ) {
+				echo $field; // phpcs:ignore WordPress.XSS.EscapeOutput.OutputNotEscaped
+			}
 			?>
 			<?php do_action( 'woocommerce_echeck_form_end', $this->id ); ?>
 			<div class="clear"></div>
-		</fieldset><?php
+		</fieldset>
+		<?php
 	}
 }
diff --git a/includes/gateways/cod/class-wc-gateway-cod.php b/includes/gateways/cod/class-wc-gateway-cod.php
index a20be862050..06c594a941e 100644
--- a/includes/gateways/cod/class-wc-gateway-cod.php
+++ b/includes/gateways/cod/class-wc-gateway-cod.php
@@ -1,7 +1,12 @@
 <?php
+/**
+ * Class WC_Gateway_COD file.
+ *
+ * @package WooCommerce\Gateways
+ */
 
 if ( ! defined( 'ABSPATH' ) ) {
-	exit; // Exit if accessed directly
+	exit; // Exit if accessed directly.
 }
 
 /**
@@ -9,11 +14,10 @@ if ( ! defined( 'ABSPATH' ) ) {
  *
  * Provides a Cash on Delivery Payment Gateway.
  *
- * @class 		WC_Gateway_COD
- * @extends		WC_Payment_Gateway
- * @version		2.1.0
- * @package		WooCommerce/Classes/Payment
- * @author 		WooThemes
+ * @class       WC_Gateway_COD
+ * @extends     WC_Payment_Gateway
+ * @version     2.1.0
+ * @package     WooCommerce/Classes/Payment
  */
 class WC_Gateway_COD extends WC_Payment_Gateway {
 
@@ -21,14 +25,14 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 	 * Constructor for the gateway.
 	 */
 	public function __construct() {
-		// Setup general properties
+		// Setup general properties.
 		$this->setup_properties();
 
-		// Load the settings
+		// Load the settings.
 		$this->init_form_fields();
 		$this->init_settings();
 
-		// Get settings
+		// Get settings.
 		$this->title              = $this->get_option( 'title' );
 		$this->description        = $this->get_option( 'description' );
 		$this->instructions       = $this->get_option( 'instructions' );
@@ -39,7 +43,7 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 		add_action( 'woocommerce_thankyou_' . $this->id, array( $this, 'thankyou_page' ) );
 		add_filter( 'woocommerce_payment_complete_order_status', array( $this, 'change_payment_complete_order_status' ), 10, 3 );
 
-		// Customer Emails
+		// Customer Emails.
 		add_action( 'woocommerce_email_before_order_table', array( $this, 'email_instructions' ), 10, 3 );
 	}
 
@@ -65,28 +69,28 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 		}
 
 		$this->form_fields = array(
-			'enabled' => array(
+			'enabled'            => array(
 				'title'       => __( 'Enable/Disable', 'woocommerce' ),
 				'label'       => __( 'Enable cash on delivery', 'woocommerce' ),
 				'type'        => 'checkbox',
 				'description' => '',
 				'default'     => 'no',
 			),
-			'title' => array(
+			'title'              => array(
 				'title'       => __( 'Title', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'Payment method description that the customer will see on your checkout.', 'woocommerce' ),
 				'default'     => __( 'Cash on delivery', 'woocommerce' ),
 				'desc_tip'    => true,
 			),
-			'description' => array(
+			'description'        => array(
 				'title'       => __( 'Description', 'woocommerce' ),
 				'type'        => 'textarea',
 				'description' => __( 'Payment method description that the customer will see on your website.', 'woocommerce' ),
 				'default'     => __( 'Pay with cash upon delivery.', 'woocommerce' ),
 				'desc_tip'    => true,
 			),
-			'instructions' => array(
+			'instructions'       => array(
 				'title'       => __( 'Instructions', 'woocommerce' ),
 				'type'        => 'textarea',
 				'description' => __( 'Instructions that will be added to the thank you page.', 'woocommerce' ),
@@ -107,12 +111,12 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 				),
 			),
 			'enable_for_virtual' => array(
-				'title'             => __( 'Accept for virtual orders', 'woocommerce' ),
-				'label'             => __( 'Accept COD if the order is virtual', 'woocommerce' ),
-				'type'              => 'checkbox',
-				'default'           => 'yes',
+				'title'   => __( 'Accept for virtual orders', 'woocommerce' ),
+				'label'   => __( 'Accept COD if the order is virtual', 'woocommerce' ),
+				'type'    => 'checkbox',
+				'default' => 'yes',
 			),
-	   );
+		);
 	}
 
 	/**
@@ -124,7 +128,7 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 		$order          = null;
 		$needs_shipping = false;
 
-		// Test if shipping is needed first
+		// Test if shipping is needed first.
 		if ( WC()->cart && WC()->cart->needs_shipping() ) {
 			$needs_shipping = true;
 		} elseif ( is_page( wc_get_page_id( 'checkout' ) ) && 0 < get_query_var( 'order-pay' ) ) {
@@ -132,7 +136,7 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 			$order    = wc_get_order( $order_id );
 
 			// Test if order needs shipping.
-			if ( 0 < sizeof( $order->get_items() ) ) {
+			if ( 0 < count( $order->get_items() ) ) {
 				foreach ( $order->get_items() as $item ) {
 					$_product = $item->get_product();
 					if ( $_product && $_product->needs_shipping() ) {
@@ -145,18 +149,19 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 
 		$needs_shipping = apply_filters( 'woocommerce_cart_needs_shipping', $needs_shipping );
 
-		// Virtual order, with virtual disabled
+		// Virtual order, with virtual disabled.
 		if ( ! $this->enable_for_virtual && ! $needs_shipping ) {
 			return false;
 		}
 
 		// Only apply if all packages are being shipped via chosen method, or order is virtual.
 		if ( ! empty( $this->enable_for_methods ) && $needs_shipping ) {
-			$chosen_shipping_methods = array();
+			$chosen_shipping_methods         = array();
+			$chosen_shipping_methods_session = WC()->session->get( 'chosen_shipping_methods' );
 
 			if ( is_object( $order ) ) {
 				$chosen_shipping_methods = array_unique( array_map( 'wc_get_string_before_colon', $order->get_shipping_methods() ) );
-			} elseif ( $chosen_shipping_methods_session = WC()->session->get( 'chosen_shipping_methods' ) ) {
+			} elseif ( $chosen_shipping_methods_session ) {
 				$chosen_shipping_methods = array_unique( array_map( 'wc_get_string_before_colon', $chosen_shipping_methods_session ) );
 			}
 
@@ -172,29 +177,29 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 	/**
 	 * Process the payment and return the result.
 	 *
-	 * @param int $order_id
+	 * @param int $order_id Order ID.
 	 * @return array
 	 */
 	public function process_payment( $order_id ) {
 		$order = wc_get_order( $order_id );
 
 		if ( $order->get_total() > 0 ) {
-			// Mark as processing or on-hold (payment won't be taken until delivery)
+			// Mark as processing or on-hold (payment won't be taken until delivery).
 			$order->update_status( apply_filters( 'woocommerce_cod_process_payment_order_status', $order->has_downloadable_item() ? 'on-hold' : 'processing', $order ), __( 'Payment to be made upon delivery.', 'woocommerce' ) );
 		} else {
 			$order->payment_complete();
 		}
 
-		// Reduce stock levels
+		// Reduce stock levels.
 		wc_reduce_stock_levels( $order_id );
 
-		// Remove cart
+		// Remove cart.
 		WC()->cart->empty_cart();
 
-		// Return thankyou redirect
+		// Return thankyou redirect.
 		return array(
-			'result' 	=> 'success',
-			'redirect'	=> $this->get_return_url( $order ),
+			'result'   => 'success',
+			'redirect' => $this->get_return_url( $order ),
 		);
 	}
 
@@ -203,7 +208,7 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 	 */
 	public function thankyou_page() {
 		if ( $this->instructions ) {
-			echo wpautop( wptexturize( $this->instructions ) );
+			echo wp_kses_post( wpautop( wptexturize( $this->instructions ) ) );
 		}
 	}
 
@@ -211,9 +216,9 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 	 * Change payment complete order status to completed for COD orders.
 	 *
 	 * @since  3.1.0
-	 * @param  string $status
-	 * @param  int $order_id
-	 * @param  WC_Order $order
+	 * @param  string         $status Current order status.
+	 * @param  int            $order_id Order ID.
+	 * @param  WC_Order|false $order Order object.
 	 * @return string
 	 */
 	public function change_payment_complete_order_status( $status, $order_id = 0, $order = false ) {
@@ -227,13 +232,13 @@ class WC_Gateway_COD extends WC_Payment_Gateway {
 	 * Add content to the WC emails.
 	 *
 	 * @access public
-	 * @param WC_Order $order
-	 * @param bool $sent_to_admin
-	 * @param bool $plain_text
+	 * @param WC_Order $order Order object.
+	 * @param bool     $sent_to_admin  Sent to admin.
+	 * @param bool     $plain_text Email format: plain text or HTML.
 	 */
 	public function email_instructions( $order, $sent_to_admin, $plain_text = false ) {
 		if ( $this->instructions && ! $sent_to_admin && $this->id === $order->get_payment_method() ) {
-			echo wpautop( wptexturize( $this->instructions ) ) . PHP_EOL;
+			echo wp_kses_post( wpautop( wptexturize( $this->instructions ) ) . PHP_EOL );
 		}
 	}
 }
diff --git a/includes/gateways/paypal/class-wc-gateway-paypal.php b/includes/gateways/paypal/class-wc-gateway-paypal.php
index f81211b159d..8b3f73d8940 100644
--- a/includes/gateways/paypal/class-wc-gateway-paypal.php
+++ b/includes/gateways/paypal/class-wc-gateway-paypal.php
@@ -4,11 +4,10 @@
  *
  * Provides a PayPal Standard Payment Gateway.
  *
- * @class 		WC_Gateway_Paypal
- * @extends		WC_Payment_Gateway
- * @version		2.3.0
- * @package		WooCommerce/Classes/Payment
- * @author 		WooThemes
+ * @class       WC_Gateway_Paypal
+ * @extends     WC_Payment_Gateway
+ * @version     2.3.0
+ * @package     WooCommerce/Classes/Payment
  */
 
 if ( ! defined( 'ABSPATH' ) ) {
@@ -20,20 +19,29 @@ if ( ! defined( 'ABSPATH' ) ) {
  */
 class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
-	/** @var bool Whether or not logging is enabled */
+	/**
+	 * Whether or not logging is enabled
+	 *
+	 * @var bool
+	 */
 	public static $log_enabled = false;
 
-	/** @var WC_Logger Logger instance */
+	/**
+	 * Logger instance
+	 *
+	 * @var WC_Logger
+	 */
 	public static $log = false;
 
 	/**
 	 * Constructor for the gateway.
 	 */
 	public function __construct() {
-		$this->id                 = 'paypal';
-		$this->has_fields         = false;
-		$this->order_button_text  = __( 'Proceed to PayPal', 'woocommerce' );
-		$this->method_title       = __( 'PayPal', 'woocommerce' );
+		$this->id                = 'paypal';
+		$this->has_fields        = false;
+		$this->order_button_text = __( 'Proceed to PayPal', 'woocommerce' );
+		$this->method_title      = __( 'PayPal', 'woocommerce' );
+		/* translators: %s: Link to WC system status page */
 		$this->method_description = sprintf( __( 'PayPal Standard sends customers to PayPal to enter their payment information. PayPal IPN requires fsockopen/cURL support to update order statuses after payment. Check the <a href="%s">system status</a> page for more details.', 'woocommerce' ), admin_url( 'admin.php?page=wc-status' ) );
 		$this->supports           = array(
 			'products',
@@ -53,9 +61,10 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 		$this->receiver_email = $this->get_option( 'receiver_email', $this->email );
 		$this->identity_token = $this->get_option( 'identity_token' );
 
-		self::$log_enabled    = $this->debug;
+		self::$log_enabled = $this->debug;
 
 		if ( $this->testmode ) {
+			/* translators: %s: Link to PayPal sandbox testing guide page */
 			$this->description .= ' ' . sprintf( __( 'SANDBOX ENABLED. You can use sandbox testing accounts only. See the <a href="%s">PayPal Sandbox Testing Guide</a> for more details.', 'woocommerce' ), 'https://developer.paypal.com/docs/classic/lifecycle/ug_sandbox/' );
 			$this->description  = trim( $this->description );
 		}
@@ -68,11 +77,11 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 		if ( ! $this->is_valid_for_use() ) {
 			$this->enabled = 'no';
 		} else {
-			include_once( dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-ipn-handler.php' );
+			include_once dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-ipn-handler.php';
 			new WC_Gateway_Paypal_IPN_Handler( $this->testmode, $this->receiver_email );
 
 			if ( $this->identity_token ) {
-				include_once( dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-pdt-handler.php' );
+				include_once dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-pdt-handler.php';
 				new WC_Gateway_Paypal_PDT_Handler( $this->testmode, $this->identity_token );
 			}
 		}
@@ -82,8 +91,8 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 	 * Logging method.
 	 *
 	 * @param string $message Log message.
-	 * @param string $level   Optional. Default 'info'.
-	 *     emergency|alert|critical|error|warning|notice|info|debug
+	 * @param string $level Optional. Default 'info'. Possible values:
+	 *                      emergency|alert|critical|error|warning|notice|info|debug.
 	 */
 	public static function log( $message, $level = 'info' ) {
 		if ( self::$log_enabled ) {
@@ -96,6 +105,7 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
 	/**
 	 * Get gateway icon.
+	 *
 	 * @return string
 	 */
 	public function get_icon() {
@@ -113,7 +123,8 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
 	/**
 	 * Get the link for an icon based on country.
-	 * @param  string $country
+	 *
+	 * @param  string $country Country two letter code.
 	 * @return string
 	 */
 	protected function get_icon_url( $country ) {
@@ -121,9 +132,9 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 		$home_counties = array( 'BE', 'CZ', 'DK', 'HU', 'IT', 'JP', 'NL', 'NO', 'ES', 'SE', 'TR', 'IN' );
 		$countries     = array( 'DZ', 'AU', 'BH', 'BQ', 'BW', 'CA', 'CN', 'CW', 'FI', 'FR', 'DE', 'GR', 'HK', 'ID', 'JO', 'KE', 'KW', 'LU', 'MY', 'MA', 'OM', 'PH', 'PL', 'PT', 'QA', 'IE', 'RU', 'BL', 'SX', 'MF', 'SA', 'SG', 'SK', 'KR', 'SS', 'TW', 'TH', 'AE', 'GB', 'US', 'VN' );
 
-		if ( in_array( $country, $home_counties ) ) {
-			return  $url . '/webapps/mpp/home';
-		} elseif ( in_array( $country, $countries ) ) {
+		if ( in_array( $country, $home_counties, true ) ) {
+			return $url . '/webapps/mpp/home';
+		} elseif ( in_array( $country, $countries, true ) ) {
 			return $url . '/webapps/mpp/paypal-popup';
 		} else {
 			return $url . '/cgi-bin/webscr?cmd=xpt/Marketing/general/WIPaypal-outside';
@@ -138,74 +149,82 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 	 */
 	protected function get_icon_image( $country ) {
 		switch ( $country ) {
-			case 'US' :
-			case 'NZ' :
-			case 'CZ' :
-			case 'HU' :
-			case 'MY' :
+			case 'US':
+			case 'NZ':
+			case 'CZ':
+			case 'HU':
+			case 'MY':
 				$icon = 'https://www.paypalobjects.com/webstatic/mktg/logo/AM_mc_vs_dc_ae.jpg';
-			break;
-			case 'TR' :
+				break;
+			case 'TR':
 				$icon = 'https://www.paypalobjects.com/webstatic/mktg/logo-center/logo_paypal_odeme_secenekleri.jpg';
-			break;
-			case 'GB' :
+				break;
+			case 'GB':
 				$icon = 'https://www.paypalobjects.com/webstatic/mktg/Logo/AM_mc_vs_ms_ae_UK.png';
-			break;
-			case 'MX' :
+				break;
+			case 'MX':
 				$icon = array(
 					'https://www.paypal.com/es_XC/Marketing/i/banner/paypal_visa_mastercard_amex.png',
 					'https://www.paypal.com/es_XC/Marketing/i/banner/paypal_debit_card_275x60.gif',
 				);
-			break;
-			case 'FR' :
+				break;
+			case 'FR':
 				$icon = 'https://www.paypalobjects.com/webstatic/mktg/logo-center/logo_paypal_moyens_paiement_fr.jpg';
-			break;
-			case 'AU' :
+				break;
+			case 'AU':
 				$icon = 'https://www.paypalobjects.com/webstatic/en_AU/mktg/logo/Solutions-graphics-1-184x80.jpg';
-			break;
-			case 'DK' :
+				break;
+			case 'DK':
 				$icon = 'https://www.paypalobjects.com/webstatic/mktg/logo-center/logo_PayPal_betalingsmuligheder_dk.jpg';
-			break;
-			case 'RU' :
+				break;
+			case 'RU':
 				$icon = 'https://www.paypalobjects.com/webstatic/ru_RU/mktg/business/pages/logo-center/AM_mc_vs_dc_ae.jpg';
-			break;
-			case 'NO' :
+				break;
+			case 'NO':
 				$icon = 'https://www.paypalobjects.com/webstatic/mktg/logo-center/banner_pl_just_pp_319x110.jpg';
-			break;
-			case 'CA' :
+				break;
+			case 'CA':
 				$icon = 'https://www.paypalobjects.com/webstatic/en_CA/mktg/logo-image/AM_mc_vs_dc_ae.jpg';
-			break;
-			case 'HK' :
+				break;
+			case 'HK':
 				$icon = 'https://www.paypalobjects.com/webstatic/en_HK/mktg/logo/AM_mc_vs_dc_ae.jpg';
-			break;
-			case 'SG' :
+				break;
+			case 'SG':
 				$icon = 'https://www.paypalobjects.com/webstatic/en_SG/mktg/Logos/AM_mc_vs_dc_ae.jpg';
-			break;
-			case 'TW' :
+				break;
+			case 'TW':
 				$icon = 'https://www.paypalobjects.com/webstatic/en_TW/mktg/logos/AM_mc_vs_dc_ae.jpg';
-			break;
-			case 'TH' :
+				break;
+			case 'TH':
 				$icon = 'https://www.paypalobjects.com/webstatic/en_TH/mktg/Logos/AM_mc_vs_dc_ae.jpg';
-			break;
-			case 'JP' :
+				break;
+			case 'JP':
 				$icon = 'https://www.paypal.com/ja_JP/JP/i/bnr/horizontal_solution_4_jcb.gif';
 				break;
-			case 'IN' :
+			case 'IN':
 				$icon = 'https://www.paypalobjects.com/webstatic/mktg/logo/AM_mc_vs_dc_ae.jpg';
 				break;
-			default :
+			default:
 				$icon = WC_HTTPS::force_https_url( WC()->plugin_url() . '/includes/gateways/paypal/assets/images/paypal.png' );
-			break;
+				break;
 		}
 		return apply_filters( 'woocommerce_paypal_icon', $icon );
 	}
 
 	/**
 	 * Check if this gateway is enabled and available in the user's country.
+	 *
 	 * @return bool
 	 */
 	public function is_valid_for_use() {
-		return in_array( get_woocommerce_currency(), apply_filters( 'woocommerce_paypal_supported_currencies', array( 'AUD', 'BRL', 'CAD', 'MXN', 'NZD', 'HKD', 'SGD', 'USD', 'EUR', 'JPY', 'TRY', 'NOK', 'CZK', 'DKK', 'HUF', 'ILS', 'MYR', 'PHP', 'PLN', 'SEK', 'CHF', 'TWD', 'THB', 'GBP', 'RMB', 'RUB', 'INR' ) ) );
+		return in_array(
+			get_woocommerce_currency(),
+			apply_filters(
+				'woocommerce_paypal_supported_currencies',
+				array( 'AUD', 'BRL', 'CAD', 'MXN', 'NZD', 'HKD', 'SGD', 'USD', 'EUR', 'JPY', 'TRY', 'NOK', 'CZK', 'DKK', 'HUF', 'ILS', 'MYR', 'PHP', 'PLN', 'SEK', 'CHF', 'TWD', 'THB', 'GBP', 'RMB', 'RUB', 'INR' )
+			),
+			true
+		);
 	}
 
 	/**
@@ -219,7 +238,11 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 			parent::admin_options();
 		} else {
 			?>
-			<div class="inline error"><p><strong><?php _e( 'Gateway disabled', 'woocommerce' ); ?></strong>: <?php _e( 'PayPal does not support your store currency.', 'woocommerce' ); ?></p></div>
+			<div class="inline error">
+				<p>
+					<strong><?php esc_html_e( 'Gateway disabled', 'woocommerce' ); ?></strong>: <?php esc_html_e( 'PayPal does not support your store currency.', 'woocommerce' ); ?>
+				</p>
+			</div>
 			<?php
 		}
 	}
@@ -228,12 +251,13 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 	 * Initialise Gateway Settings Form Fields.
 	 */
 	public function init_form_fields() {
-		$this->form_fields = include( 'includes/settings-paypal.php' );
+		$this->form_fields = include 'includes/settings-paypal.php';
 	}
 
 	/**
 	 * Get the transaction URL.
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return string
 	 */
 	public function get_transaction_url( $order ) {
@@ -247,11 +271,12 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
 	/**
 	 * Process the payment and return the result.
-	 * @param  int $order_id
+	 *
+	 * @param  int $order_id Order ID.
 	 * @return array
 	 */
 	public function process_payment( $order_id ) {
-		include_once( dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-request.php' );
+		include_once dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-request.php';
 
 		$order          = wc_get_order( $order_id );
 		$paypal_request = new WC_Gateway_Paypal_Request( $this );
@@ -264,7 +289,8 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
 	/**
 	 * Can the order be refunded via PayPal?
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return bool
 	 */
 	public function can_refund_order( $order ) {
@@ -275,7 +301,7 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 	 * Init the API class and set the username/password etc.
 	 */
 	protected function init_api() {
-		include_once( dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-api-handler.php' );
+		include_once dirname( __FILE__ ) . '/includes/class-wc-gateway-paypal-api-handler.php';
 
 		WC_Gateway_Paypal_API_Handler::$api_username  = $this->testmode ? $this->get_option( 'sandbox_api_username' ) : $this->get_option( 'api_username' );
 		WC_Gateway_Paypal_API_Handler::$api_password  = $this->testmode ? $this->get_option( 'sandbox_api_password' ) : $this->get_option( 'api_password' );
@@ -285,9 +311,10 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
 	/**
 	 * Process a refund if supported.
-	 * @param  int    $order_id
-	 * @param  float  $amount
-	 * @param  string $reason
+	 *
+	 * @param  int    $order_id Order ID.
+	 * @param  float  $amount Refund amount.
+	 * @param  string $reason Refund reason.
 	 * @return bool|WP_Error
 	 */
 	public function process_refund( $order_id, $amount = null, $reason = '' ) {
@@ -309,21 +336,23 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
 		$this->log( 'Refund Result: ' . wc_print_r( $result, true ) );
 
-		switch ( strtolower( $result->ACK ) ) {
+		switch ( strtolower( $result->ACK ) ) { // phpcs:ignore WordPress.NamingConventions.ValidVariableName.NotSnakeCaseMemberVar
 			case 'success':
 			case 'successwithwarning':
-				$order->add_order_note( sprintf( __( 'Refunded %1$s - Refund ID: %2$s', 'woocommerce' ), $result->GROSSREFUNDAMT, $result->REFUNDTRANSACTIONID ) );
+				$order->add_order_note(
+					/* translators: 1: Refund amount, 2: Refund ID */
+					sprintf( __( 'Refunded %1$s - Refund ID: %2$s', 'woocommerce' ), $result->GROSSREFUNDAMT, $result->REFUNDTRANSACTIONID ) // phpcs:ignore WordPress.NamingConventions.ValidVariableName.NotSnakeCaseMemberVar
+				);
 				return true;
-			break;
 		}
 
-		return isset( $result->L_LONGMESSAGE0 ) ? new WP_Error( 'error', $result->L_LONGMESSAGE0 ) : false;
+		return isset( $result->L_LONGMESSAGE0 ) ? new WP_Error( 'error', $result->L_LONGMESSAGE0 ) : false; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.NotSnakeCaseMemberVar
 	}
 
 	/**
 	 * Capture payment when the order is changed from on-hold to complete or processing
 	 *
-	 * @param  int $order_id
+	 * @param  int $order_id Order ID.
 	 */
 	public function capture_payment( $order_id ) {
 		$order = wc_get_order( $order_id );
@@ -334,24 +363,29 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 
 			if ( is_wp_error( $result ) ) {
 				$this->log( 'Capture Failed: ' . $result->get_error_message(), 'error' );
+				/* translators: %s: Paypal gateway error message */
 				$order->add_order_note( sprintf( __( 'Payment could not captured: %s', 'woocommerce' ), $result->get_error_message() ) );
 				return;
 			}
 
 			$this->log( 'Capture Result: ' . wc_print_r( $result, true ) );
 
+			// phpcs:disable WordPress.NamingConventions.ValidVariableName.NotSnakeCaseMemberVar
 			if ( ! empty( $result->PAYMENTSTATUS ) ) {
 				switch ( $result->PAYMENTSTATUS ) {
-					case 'Completed' :
+					case 'Completed':
+						/* translators: 1: Amount, 2: Authorization ID, 3: Transaction ID */
 						$order->add_order_note( sprintf( __( 'Payment of %1$s was captured - Auth ID: %2$s, Transaction ID: %3$s', 'woocommerce' ), $result->AMT, $result->AUTHORIZATIONID, $result->TRANSACTIONID ) );
 						update_post_meta( $order->get_id(), '_paypal_status', $result->PAYMENTSTATUS );
 						update_post_meta( $order->get_id(), '_transaction_id', $result->TRANSACTIONID );
-					break;
-					default :
+						break;
+					default:
+						/* translators: 1: Authorization ID, 2: Payment status */
 						$order->add_order_note( sprintf( __( 'Payment could not captured - Auth ID: %1$s, Status: %2$s', 'woocommerce' ), $result->AUTHORIZATIONID, $result->PAYMENTSTATUS ) );
-					break;
+						break;
 				}
 			}
+			// phpcs:enable
 		}
 	}
 
@@ -362,7 +396,7 @@ class WC_Gateway_Paypal extends WC_Payment_Gateway {
 	 */
 	public function admin_scripts() {
 		$screen    = get_current_screen();
-		$screen_id = $screen ? $screen->id: '';
+		$screen_id = $screen ? $screen->id : '';
 
 		if ( 'woocommerce_page_wc-settings' !== $screen_id ) {
 			return;
diff --git a/includes/gateways/paypal/includes/class-wc-gateway-paypal-api-handler.php b/includes/gateways/paypal/includes/class-wc-gateway-paypal-api-handler.php
index 9ed597cb91c..445e250bed5 100644
--- a/includes/gateways/paypal/includes/class-wc-gateway-paypal-api-handler.php
+++ b/includes/gateways/paypal/includes/class-wc-gateway-paypal-api-handler.php
@@ -1,4 +1,9 @@
 <?php
+/**
+ * Class WC_Gateway_Paypal_API_Handler file.
+ *
+ * @package WooCommerce\Gateways
+ */
 
 if ( ! defined( 'ABSPATH' ) ) {
 	exit;
@@ -6,27 +11,45 @@ if ( ! defined( 'ABSPATH' ) ) {
 
 /**
  * Handles Refunds and other API requests such as capture.
+ *
  * @since 3.0.0
  */
 class WC_Gateway_Paypal_API_Handler {
 
-	/** @var string API Username */
+	/**
+	 * API Username
+	 *
+	 * @var string
+	 */
 	public static $api_username;
 
-	/** @var string API Password */
+	/**
+	 * API Password
+	 *
+	 * @var string
+	 */
 	public static $api_password;
 
-	/** @var string API Signature */
+	/**
+	 * API Signature
+	 *
+	 * @var string
+	 */
 	public static $api_signature;
 
-	/** @var bool Sandbox */
+	/**
+	 * Sandbox
+	 *
+	 * @var bool
+	 */
 	public static $sandbox = false;
 
 	/**
 	 * Get capture request args.
 	 * See https://developer.paypal.com/docs/classic/api/merchant/DoCapture_API_Operation_NVP/.
-	 * @param  WC_Order $order
-	 * @param  float    $amount
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  float    $amount Amount.
 	 * @return array
 	 */
 	public static function get_capture_request( $order, $amount = null ) {
@@ -46,9 +69,10 @@ class WC_Gateway_Paypal_API_Handler {
 
 	/**
 	 * Get refund request args.
-	 * @param  WC_Order $order
-	 * @param  float    $amount
-	 * @param  string   $reason
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  float    $amount Refund amount.
+	 * @param  string   $reason Refund reason.
 	 * @return array
 	 */
 	public static function get_refund_request( $order, $amount = null, $reason = '' ) {
@@ -72,8 +96,9 @@ class WC_Gateway_Paypal_API_Handler {
 
 	/**
 	 * Capture an authorization.
-	 * @param  WC_Order $order
-	 * @param  float $amount
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  float    $amount Amount.
 	 * @return object Either an object of name value pairs for a success, or a WP_ERROR object.
 	 */
 	public static function do_capture( $order, $amount = null ) {
@@ -103,9 +128,10 @@ class WC_Gateway_Paypal_API_Handler {
 
 	/**
 	 * Refund an order via PayPal.
-	 * @param  WC_Order $order
-	 * @param  float    $amount
-	 * @param  string   $reason
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  float    $amount Refund amount.
+	 * @param  string   $reason Refund reason.
 	 * @return object Either an object of name value pairs for a success, or a WP_ERROR object.
 	 */
 	public static function refund_transaction( $order, $amount = null, $reason = '' ) {
@@ -136,12 +162,32 @@ class WC_Gateway_Paypal_API_Handler {
 
 /**
  * Here for backwards compatibility.
+ *
  * @since 3.0.0
  */
 class WC_Gateway_Paypal_Refund extends WC_Gateway_Paypal_API_Handler {
+	/**
+	 * Get refund request args. Proxy to WC_Gateway_Paypal_API_Handler::get_refund_request().
+	 *
+	 * @param WC_Order $order Order object.
+	 * @param float    $amount Refund amount.
+	 * @param string   $reason Refund reason.
+	 *
+	 * @return array
+	 */
 	public static function get_request( $order, $amount = null, $reason = '' ) {
 		return self::get_refund_request( $order, $amount, $reason );
 	}
+
+	/**
+	 * Process an order refund.
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  float    $amount Refund amount.
+	 * @param  string   $reason Refund reason.
+	 * @param  bool     $sandbox Whether to use sandbox mode or not.
+	 * @return object Either an object of name value pairs for a success, or a WP_ERROR object.
+	 */
 	public static function refund_order( $order, $amount = null, $reason = '', $sandbox = false ) {
 		if ( $sandbox ) {
 			self::$sandbox = $sandbox;
diff --git a/includes/gateways/paypal/includes/class-wc-gateway-paypal-pdt-handler.php b/includes/gateways/paypal/includes/class-wc-gateway-paypal-pdt-handler.php
index 5e85cb73773..24d119b1c8f 100644
--- a/includes/gateways/paypal/includes/class-wc-gateway-paypal-pdt-handler.php
+++ b/includes/gateways/paypal/includes/class-wc-gateway-paypal-pdt-handler.php
@@ -1,24 +1,33 @@
 <?php
+/**
+ * Class WC_Gateway_Paypal_PDT_Handler file.
+ *
+ * @package WooCommerce\Gateways
+ */
 
 if ( ! defined( 'ABSPATH' ) ) {
 	exit;
 }
 
-include_once( dirname( __FILE__ ) . '/class-wc-gateway-paypal-response.php' );
+require_once dirname( __FILE__ ) . '/class-wc-gateway-paypal-response.php';
 
 /**
  * Handle PDT Responses from PayPal.
  */
 class WC_Gateway_Paypal_PDT_Handler extends WC_Gateway_Paypal_Response {
 
-	/** @var string identity_token for PDT support */
+	/**
+	 * Identity token for PDT support
+	 *
+	 * @var string
+	 */
 	protected $identity_token;
 
 	/**
 	 * Constructor.
 	 *
-	 * @param bool $sandbox
-	 * @param string $identity_token
+	 * @param bool   $sandbox Whether to use sandbox mode or not.
+	 * @param string $identity_token Identity token for PDT support.
 	 */
 	public function __construct( $sandbox = false, $identity_token = '' ) {
 		add_action( 'woocommerce_thankyou_paypal', array( $this, 'check_response' ) );
@@ -35,20 +44,20 @@ class WC_Gateway_Paypal_PDT_Handler extends WC_Gateway_Paypal_Response {
 	 */
 	protected function validate_transaction( $transaction ) {
 		$pdt = array(
-			'body' 			=> array(
+			'body'        => array(
 				'cmd' => '_notify-synch',
 				'tx'  => $transaction,
 				'at'  => $this->identity_token,
 			),
-			'timeout' 		=> 60,
-			'httpversion'   => '1.1',
-			'user-agent'	=> 'WooCommerce/' . WC_VERSION,
+			'timeout'     => 60,
+			'httpversion' => '1.1',
+			'user-agent'  => 'WooCommerce/' . WC_VERSION,
 		);
 
 		// Post back to get a response.
 		$response = wp_safe_remote_post( $this->sandbox ? 'https://www.sandbox.paypal.com/cgi-bin/webscr' : 'https://www.paypal.com/cgi-bin/webscr', $pdt );
 
-		if ( is_wp_error( $response ) || strpos( $response['body'], "SUCCESS" ) !== 0 ) {
+		if ( is_wp_error( $response ) || strpos( $response['body'], 'SUCCESS' ) !== 0 ) {
 			return false;
 		}
 
@@ -57,7 +66,7 @@ class WC_Gateway_Paypal_PDT_Handler extends WC_Gateway_Paypal_Response {
 		$transaction_results = array();
 
 		foreach ( $transaction_result as $line ) {
-			$line                            = explode( "=", $line );
+			$line                            = explode( '=', $line );
 			$transaction_results[ $line[0] ] = isset( $line[1] ) ? $line[1] : '';
 		}
 
@@ -78,12 +87,14 @@ class WC_Gateway_Paypal_PDT_Handler extends WC_Gateway_Paypal_Response {
 			return;
 		}
 
-		$order_id    = wc_clean( stripslashes( $_REQUEST['cm'] ) );
-		$status      = wc_clean( strtolower( stripslashes( $_REQUEST['st'] ) ) );
-		$amount      = wc_clean( stripslashes( $_REQUEST['amt'] ) );
-		$transaction = wc_clean( stripslashes( $_REQUEST['tx'] ) );
+		$order_id    = wc_clean( wp_unslash( $_REQUEST['cm'] ) );
+		$status      = wc_clean( strtolower( wp_unslash( $_REQUEST['st'] ) ) ); // phpcs:ignore WordPress.VIP.ValidatedSanitizedInput.InputNotSanitized
+		$amount      = wc_clean( wp_unslash( $_REQUEST['amt'] ) ); // phpcs:ignore WordPress.VIP.ValidatedSanitizedInput.InputNotValidated
+		$transaction = wc_clean( wp_unslash( $_REQUEST['tx'] ) );
 
-		if ( ! ( $order = $this->get_paypal_order( $order_id ) ) || ! $order->has_status( 'pending' ) ) {
+		$order = $this->get_paypal_order( $order_id );
+
+		if ( ! $order || ! $order->has_status( 'pending' ) ) {
 			return false;
 		}
 
@@ -95,12 +106,13 @@ class WC_Gateway_Paypal_PDT_Handler extends WC_Gateway_Paypal_Response {
 			update_post_meta( $order->get_id(), '_paypal_status', $status );
 			update_post_meta( $order->get_id(), '_transaction_id', $transaction );
 
-	 		if ( 'completed' === $status ) {
-				if ( $order->get_total() != $amount ) {
+			if ( 'completed' === $status ) {
+				if ( $order->get_total() !== $amount ) {
 					WC_Gateway_Paypal::log( 'Payment error: Amounts do not match (amt ' . $amount . ')', 'error' );
+					/* translators: 1: Payment amount */
 					$this->payment_on_hold( $order, sprintf( __( 'Validation error: PayPal amounts do not match (amt %s).', 'woocommerce' ), $amount ) );
 				} else {
-					$this->payment_complete( $order, $transaction,  __( 'PDT payment completed', 'woocommerce' ) );
+					$this->payment_complete( $order, $transaction, __( 'PDT payment completed', 'woocommerce' ) );
 
 					// Log paypal transaction fee and other meta data.
 					if ( ! empty( $transaction_result['mc_fee'] ) ) {
@@ -123,6 +135,7 @@ class WC_Gateway_Paypal_PDT_Handler extends WC_Gateway_Paypal_Response {
 				if ( 'authorization' === $transaction_result['pending_reason'] ) {
 					$this->payment_on_hold( $order, __( 'Payment authorized. Change payment status to processing or complete to capture funds.', 'woocommerce' ) );
 				} else {
+					/* translators: 1: Pending reason */
 					$this->payment_on_hold( $order, sprintf( __( 'Payment pending (%s).', 'woocommerce' ), $transaction_result['pending_reason'] ) );
 				}
 			}
diff --git a/includes/gateways/paypal/includes/class-wc-gateway-paypal-request.php b/includes/gateways/paypal/includes/class-wc-gateway-paypal-request.php
index 44076dcd62b..3df9a58a0c2 100644
--- a/includes/gateways/paypal/includes/class-wc-gateway-paypal-request.php
+++ b/includes/gateways/paypal/includes/class-wc-gateway-paypal-request.php
@@ -1,4 +1,9 @@
 <?php
+/**
+ * Class WC_Gateway_Paypal_Request file.
+ *
+ * @package WooCommerce\Gateways
+ */
 
 if ( ! defined( 'ABSPATH' ) ) {
 	exit;
@@ -11,25 +16,29 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Stores line items to send to PayPal.
+	 *
 	 * @var array
 	 */
 	protected $line_items = array();
 
 	/**
 	 * Pointer to gateway making the request.
+	 *
 	 * @var WC_Gateway_Paypal
 	 */
 	protected $gateway;
 
 	/**
 	 * Endpoint for requests from PayPal.
+	 *
 	 * @var string
 	 */
 	protected $notify_url;
 
 	/**
 	 * Constructor.
-	 * @param WC_Gateway_Paypal $gateway
+	 *
+	 * @param WC_Gateway_Paypal $gateway Paypal gateway object.
 	 */
 	public function __construct( $gateway ) {
 		$this->gateway    = $gateway;
@@ -38,8 +47,9 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get the PayPal request URL for an order.
-	 * @param  WC_Order $order
-	 * @param  bool     $sandbox
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  bool     $sandbox Whether to use sandbox mode or not.
 	 * @return string
 	 */
 	public function get_request_url( $order, $sandbox = false ) {
@@ -57,8 +67,8 @@ class WC_Gateway_Paypal_Request {
 	/**
 	 * Limit length of an arg.
 	 *
-	 * @param  string  $string
-	 * @param  integer $limit
+	 * @param  string  $string Argument to limit.
+	 * @param  integer $limit Limit size in characters.
 	 * @return string
 	 */
 	protected function limit_length( $string, $limit = 127 ) {
@@ -70,53 +80,62 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get PayPal Args for passing to PP.
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return array
 	 */
 	protected function get_paypal_args( $order ) {
 		WC_Gateway_Paypal::log( 'Generating payment form for order ' . $order->get_order_number() . '. Notify URL: ' . $this->notify_url );
 
-		return apply_filters( 'woocommerce_paypal_args', array_merge(
-			array(
-				'cmd'           => '_cart',
-				'business'      => $this->gateway->get_option( 'email' ),
-				'no_note'       => 1,
-				'currency_code' => get_woocommerce_currency(),
-				'charset'       => 'utf-8',
-				'rm'            => is_ssl() ? 2 : 1,
-				'upload'        => 1,
-				'return'        => esc_url_raw( add_query_arg( 'utm_nooverride', '1', $this->gateway->get_return_url( $order ) ) ),
-				'cancel_return' => esc_url_raw( $order->get_cancel_order_url_raw() ),
-				'page_style'    => $this->gateway->get_option( 'page_style' ),
-				'image_url'     => esc_url_raw( $this->gateway->get_option( 'image_url' ) ),
-				'paymentaction' => $this->gateway->get_option( 'paymentaction' ),
-				'bn'            => 'WooThemes_Cart',
-				'invoice'       => $this->limit_length( $this->gateway->get_option( 'invoice_prefix' ) . $order->get_order_number(), 127 ),
-				'custom'        => json_encode( array( 'order_id' => $order->get_id(), 'order_key' => $order->get_order_key() ) ),
-				'notify_url'    => $this->limit_length( $this->notify_url, 255 ),
-				'first_name'    => $this->limit_length( $order->get_billing_first_name(), 32 ),
-				'last_name'     => $this->limit_length( $order->get_billing_last_name(), 64 ),
-				'address1'      => $this->limit_length( $order->get_billing_address_1(), 100 ),
-				'address2'      => $this->limit_length( $order->get_billing_address_2(), 100 ),
-				'city'          => $this->limit_length( $order->get_billing_city(), 40 ),
-				'state'         => $this->get_paypal_state( $order->get_billing_country(), $order->get_billing_state() ),
-				'zip'           => $this->limit_length( wc_format_postcode( $order->get_billing_postcode(), $order->get_billing_country() ), 32 ),
-				'country'       => $this->limit_length( $order->get_billing_country(), 2 ),
-				'email'         => $this->limit_length( $order->get_billing_email() ),
-			),
-			$this->get_phone_number_args( $order ),
-			$this->get_shipping_args( $order ),
-			$this->get_line_item_args( $order )
-		), $order );
+		return apply_filters(
+			'woocommerce_paypal_args', array_merge(
+				array(
+					'cmd'           => '_cart',
+					'business'      => $this->gateway->get_option( 'email' ),
+					'no_note'       => 1,
+					'currency_code' => get_woocommerce_currency(),
+					'charset'       => 'utf-8',
+					'rm'            => is_ssl() ? 2 : 1,
+					'upload'        => 1,
+					'return'        => esc_url_raw( add_query_arg( 'utm_nooverride', '1', $this->gateway->get_return_url( $order ) ) ),
+					'cancel_return' => esc_url_raw( $order->get_cancel_order_url_raw() ),
+					'page_style'    => $this->gateway->get_option( 'page_style' ),
+					'image_url'     => esc_url_raw( $this->gateway->get_option( 'image_url' ) ),
+					'paymentaction' => $this->gateway->get_option( 'paymentaction' ),
+					'bn'            => 'WooThemes_Cart',
+					'invoice'       => $this->limit_length( $this->gateway->get_option( 'invoice_prefix' ) . $order->get_order_number(), 127 ),
+					'custom'        => wp_json_encode(
+						array(
+							'order_id'  => $order->get_id(),
+							'order_key' => $order->get_order_key(),
+						)
+					),
+					'notify_url'    => $this->limit_length( $this->notify_url, 255 ),
+					'first_name'    => $this->limit_length( $order->get_billing_first_name(), 32 ),
+					'last_name'     => $this->limit_length( $order->get_billing_last_name(), 64 ),
+					'address1'      => $this->limit_length( $order->get_billing_address_1(), 100 ),
+					'address2'      => $this->limit_length( $order->get_billing_address_2(), 100 ),
+					'city'          => $this->limit_length( $order->get_billing_city(), 40 ),
+					'state'         => $this->get_paypal_state( $order->get_billing_country(), $order->get_billing_state() ),
+					'zip'           => $this->limit_length( wc_format_postcode( $order->get_billing_postcode(), $order->get_billing_country() ), 32 ),
+					'country'       => $this->limit_length( $order->get_billing_country(), 2 ),
+					'email'         => $this->limit_length( $order->get_billing_email() ),
+				),
+				$this->get_phone_number_args( $order ),
+				$this->get_shipping_args( $order ),
+				$this->get_line_item_args( $order )
+			), $order
+		);
 	}
 
 	/**
 	 * Get phone number args for paypal request.
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return array
 	 */
 	protected function get_phone_number_args( $order ) {
-		if ( in_array( $order->get_billing_country(), array( 'US', 'CA' ) ) ) {
+		if ( in_array( $order->get_billing_country(), array( 'US', 'CA' ), true ) ) {
 			$phone_number = str_replace( array( '(', '-', ' ', ')', '.' ), '', $order->get_billing_phone() );
 			$phone_number = ltrim( $phone_number, '+1' );
 			$phone_args   = array(
@@ -134,17 +153,18 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get shipping args for paypal request.
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return array
 	 */
 	protected function get_shipping_args( $order ) {
 		$shipping_args = array();
 
-		if ( 'yes' == $this->gateway->get_option( 'send_shipping' ) ) {
+		if ( 'yes' === $this->gateway->get_option( 'send_shipping' ) ) {
 			$shipping_args['address_override'] = $this->gateway->get_option( 'address_override' ) === 'yes' ? 1 : 0;
 			$shipping_args['no_shipping']      = 0;
 
-			// If we are sending shipping, send shipping address instead of billing
+			// If we are sending shipping, send shipping address instead of billing.
 			$shipping_args['first_name'] = $this->limit_length( $order->get_shipping_first_name(), 32 );
 			$shipping_args['last_name']  = $this->limit_length( $order->get_shipping_last_name(), 64 );
 			$shipping_args['address1']   = $this->limit_length( $order->get_shipping_address_1(), 100 );
@@ -154,7 +174,7 @@ class WC_Gateway_Paypal_Request {
 			$shipping_args['country']    = $this->limit_length( $order->get_shipping_country(), 2 );
 			$shipping_args['zip']        = $this->limit_length( wc_format_postcode( $order->get_shipping_postcode(), $order->get_shipping_country() ), 32 );
 		} else {
-			$shipping_args['no_shipping']      = 1;
+			$shipping_args['no_shipping'] = 1;
 		}
 
 		return $shipping_args;
@@ -162,7 +182,8 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get line item args for paypal request.
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return array
 	 */
 	protected function get_line_item_args( $order ) {
@@ -185,17 +206,17 @@ class WC_Gateway_Paypal_Request {
 			if ( $order->get_shipping_total() > 0 && $order->get_shipping_total() < 999.99 && $this->number_format( $order->get_shipping_total() + $order->get_shipping_tax(), $order ) !== $this->number_format( $order->get_total(), $order ) ) {
 				$line_item_args['shipping_1'] = $this->number_format( $order->get_shipping_total(), $order );
 			} elseif ( $order->get_shipping_total() > 0 ) {
+				/* translators: %s: Order shipping method */
 				$this->add_line_item( sprintf( __( 'Shipping via %s', 'woocommerce' ), $order->get_shipping_method() ), 1, $this->number_format( $order->get_shipping_total(), $order ) );
 			}
 
 			$line_item_args = array_merge( $line_item_args, $this->get_line_items() );
-
-		/**
-		 * Send order as a single item.
-		 *
-		 * For shipping, we longer use shipping_1 because paypal ignores it if *any* shipping rules are within paypal, and paypal ignores anything over 5 digits (999.99 is the max).
-		 */
 		} else {
+			/**
+			 * Send order as a single item.
+			 *
+			 * For shipping, we longer use shipping_1 because paypal ignores it if *any* shipping rules are within paypal, and paypal ignores anything over 5 digits (999.99 is the max).
+			 */
 
 			$this->delete_line_items();
 
@@ -209,6 +230,7 @@ class WC_Gateway_Paypal_Request {
 			if ( $order->get_shipping_total() > 0 && $order->get_shipping_total() < 999.99 && $this->number_format( $order->get_shipping_total() + $order->get_shipping_tax(), $order ) !== $this->number_format( $order->get_total(), $order ) ) {
 				$line_item_args['shipping_1'] = $this->number_format( $order->get_shipping_total() + $order->get_shipping_tax(), $order );
 			} elseif ( $order->get_shipping_total() > 0 ) {
+				/* translators: %s: Order shipping method */
 				$this->add_line_item( sprintf( __( 'Shipping via %s', 'woocommerce' ), $order->get_shipping_method() ), 1, $this->number_format( $order->get_shipping_total() + $order->get_shipping_tax(), $order ) );
 			}
 
@@ -220,7 +242,8 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get order item names as a string.
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return string
 	 */
 	protected function get_order_item_names( $order ) {
@@ -228,13 +251,17 @@ class WC_Gateway_Paypal_Request {
 
 		foreach ( $order->get_items() as $item ) {
 			$item_name = $item->get_name();
-			$item_meta = strip_tags( wc_display_item_meta( $item, array(
-				'before'    => "",
-				'separator' => ", ",
-				'after'     => "",
-				'echo'      => false,
-				'autop'     => false,
-			) ) );
+			$item_meta = strip_tags(
+				wc_display_item_meta(
+					$item, array(
+						'before'    => '',
+						'separator' => ', ',
+						'after'     => '',
+						'echo'      => false,
+						'autop'     => false,
+					)
+				)
+			);
 
 			if ( $item_meta ) {
 				$item_name .= ' (' . $item_meta . ')';
@@ -248,19 +275,24 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get order item names as a string.
-	 * @param  WC_Order $order
-	 * @param  array $item
+	 *
+	 * @param  WC_Order      $order Order object.
+	 * @param  WC_Order_Item $item Order item object.
 	 * @return string
 	 */
 	protected function get_order_item_name( $order, $item ) {
 		$item_name = $item->get_name();
-		$item_meta = strip_tags( wc_display_item_meta( $item, array(
-			'before'    => "",
-			'separator' => ", ",
-			'after'     => "",
-			'echo'      => false,
-			'autop'     => false,
-		) ) );
+		$item_meta = strip_tags(
+			wc_display_item_meta(
+				$item, array(
+					'before'    => '',
+					'separator' => ', ',
+					'after'     => '',
+					'echo'      => false,
+					'autop'     => false,
+				)
+			)
+		);
 
 		if ( $item_meta ) {
 			$item_name .= ' (' . $item_meta . ')';
@@ -285,24 +317,25 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get line items to send to paypal.
-	 * @param  WC_Order $order
+	 *
+	 * @param  WC_Order $order Order object.
 	 * @return bool
 	 */
 	protected function prepare_line_items( $order ) {
 		$this->delete_line_items();
 		$calculated_total = 0;
 
-		// Products
+		// Products.
 		foreach ( $order->get_items( array( 'line_item', 'fee' ) ) as $item ) {
 			if ( 'fee' === $item['type'] ) {
-				$item_line_total  = $this->number_format( $item['line_total'], $order );
-				$line_item        = $this->add_line_item( $item->get_name(), 1, $item_line_total );
+				$item_line_total   = $this->number_format( $item['line_total'], $order );
+				$line_item         = $this->add_line_item( $item->get_name(), 1, $item_line_total );
 				$calculated_total += $item_line_total;
 			} else {
-				$product          = $item->get_product();
-				$sku              = $product ? $product->get_sku() : '';
-				$item_line_total  = $this->number_format( $order->get_item_subtotal( $item, false ), $order );
-				$line_item        = $this->add_line_item( $this->get_order_item_name( $order, $item ), $item->get_quantity(), $item_line_total, $sku );
+				$product           = $item->get_product();
+				$sku               = $product ? $product->get_sku() : '';
+				$item_line_total   = $this->number_format( $order->get_item_subtotal( $item, false ), $order );
+				$line_item         = $this->add_line_item( $this->get_order_item_name( $order, $item ), $item->get_quantity(), $item_line_total, $sku );
 				$calculated_total += $item_line_total * $item->get_quantity();
 			}
 
@@ -312,7 +345,7 @@ class WC_Gateway_Paypal_Request {
 		}
 
 		// Check for mismatched totals.
-		if ( $this->number_format( $calculated_total + $order->get_total_tax() + $this->round( $order->get_shipping_total(), $order ) - $this->round( $order->get_total_discount(), $order ), $order ) != $this->number_format( $order->get_total(), $order ) ) {
+		if ( $this->number_format( $calculated_total + $order->get_total_tax() + $this->round( $order->get_shipping_total(), $order ) - $this->round( $order->get_total_discount(), $order ), $order ) !== $this->number_format( $order->get_total(), $order ) ) {
 			return false;
 		}
 
@@ -321,25 +354,28 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Add PayPal Line Item.
-	 * @param  string  $item_name
-	 * @param  int     $quantity
-	 * @param  float   $amount
-	 * @param  string  $item_number
+	 *
+	 * @param  string $item_name Item name.
+	 * @param  int    $quantity Item quantity.
+	 * @param  float  $amount Amount.
+	 * @param  string $item_number Item number.
 	 * @return bool successfully added or not
 	 */
 	protected function add_line_item( $item_name, $quantity = 1, $amount = 0.0, $item_number = '' ) {
-		$index = ( sizeof( $this->line_items ) / 4 ) + 1;
+		$index = ( count( $this->line_items ) / 4 ) + 1;
 
 		if ( $amount < 0 || $index > 9 ) {
 			return false;
 		}
 
-		$item = apply_filters( 'woocommerce_paypal_line_item', array(
-			'item_name'   => html_entity_decode( wc_trim_string( $item_name ? $item_name : __( 'Item', 'woocommerce' ), 127 ), ENT_NOQUOTES, 'UTF-8' ),
-			'quantity'    => (int) $quantity,
-			'amount'      => wc_float_to_string( (float) $amount ),
-			'item_number' => $item_number,
-		), $item_name, $quantity, $amount, $item_number );
+		$item = apply_filters(
+			'woocommerce_paypal_line_item', array(
+				'item_name'   => html_entity_decode( wc_trim_string( $item_name ? $item_name : __( 'Item', 'woocommerce' ), 127 ), ENT_NOQUOTES, 'UTF-8' ),
+				'quantity'    => (int) $quantity,
+				'amount'      => wc_float_to_string( (float) $amount ),
+				'item_number' => $item_number,
+			), $item_name, $quantity, $amount, $item_number
+		);
 
 		$this->line_items[ 'item_name_' . $index ]   = $this->limit_length( $item['item_name'], 127 );
 		$this->line_items[ 'quantity_' . $index ]    = $item['quantity'];
@@ -351,8 +387,9 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Get the state to send to paypal.
-	 * @param  string $cc
-	 * @param  string $state
+	 *
+	 * @param  string $cc Country two letter code.
+	 * @param  string $state State code.
 	 * @return string
 	 */
 	protected function get_paypal_state( $cc, $state ) {
@@ -371,11 +408,12 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Check if currency has decimals.
-	 * @param  string $currency
+	 *
+	 * @param  string $currency Currency to check.
 	 * @return bool
 	 */
 	protected function currency_has_decimals( $currency ) {
-		if ( in_array( $currency, array( 'HUF', 'JPY', 'TWD' ) ) ) {
+		if ( in_array( $currency, array( 'HUF', 'JPY', 'TWD' ), true ) ) {
 			return false;
 		}
 
@@ -384,8 +422,9 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Round prices.
-	 * @param  double $price
-	 * @param  WC_Order $order
+	 *
+	 * @param  double   $price Price to round.
+	 * @param  WC_Order $order Order object.
 	 * @return double
 	 */
 	protected function round( $price, $order ) {
@@ -400,8 +439,9 @@ class WC_Gateway_Paypal_Request {
 
 	/**
 	 * Format prices.
-	 * @param  float|int $price
-	 * @param  WC_Order $order
+	 *
+	 * @param  float|int $price Price to format.
+	 * @param  WC_Order  $order Order object.
 	 * @return string
 	 */
 	protected function number_format( $price, $order ) {
diff --git a/includes/gateways/paypal/includes/class-wc-gateway-paypal-response.php b/includes/gateways/paypal/includes/class-wc-gateway-paypal-response.php
index 659bd129008..c917a8aeec3 100644
--- a/includes/gateways/paypal/includes/class-wc-gateway-paypal-response.php
+++ b/includes/gateways/paypal/includes/class-wc-gateway-paypal-response.php
@@ -1,4 +1,9 @@
 <?php
+/**
+ * Class WC_Gateway_Paypal_Response file.
+ *
+ * @package WooCommerce\Gateways
+ */
 
 if ( ! defined( 'ABSPATH' ) ) {
 	exit;
@@ -9,27 +14,34 @@ if ( ! defined( 'ABSPATH' ) ) {
  */
 abstract class WC_Gateway_Paypal_Response {
 
-	/** @var bool Sandbox mode */
+	/**
+	 * Sandbox mode
+	 *
+	 * @var bool
+	 */
 	protected $sandbox = false;
 
 	/**
 	 * Get the order from the PayPal 'Custom' variable.
-	 * @param  string $raw_custom JSON Data passed back by PayPal
+	 *
+	 * @param  string $raw_custom JSON Data passed back by PayPal.
 	 * @return bool|WC_Order object
 	 */
 	protected function get_paypal_order( $raw_custom ) {
 		// We have the data in the correct format, so get the order.
-		if ( ( $custom = json_decode( $raw_custom ) ) && is_object( $custom ) ) {
+		$custom = wp_json_decode( $raw_custom );
+		if ( $custom && is_object( $custom ) ) {
 			$order_id  = $custom->order_id;
 			$order_key = $custom->order_key;
-
-		// Nothing was found.
 		} else {
+			// Nothing was found.
 			WC_Gateway_Paypal::log( 'Order ID and key were not found in "custom".', 'error' );
 			return false;
 		}
 
-		if ( ! $order = wc_get_order( $order_id ) ) {
+		$order = wc_get_order( $order_id );
+
+		if ( ! $order ) {
 			// We have an invalid $order_id, probably because invoice_prefix has changed.
 			$order_id = wc_get_order_id_by_order_key( $order_key );
 			$order    = wc_get_order( $order_id );
@@ -45,9 +57,10 @@ abstract class WC_Gateway_Paypal_Response {
 
 	/**
 	 * Complete order, add transaction ID and note.
-	 * @param  WC_Order $order
-	 * @param  string   $txn_id
-	 * @param  string   $note
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  string   $txn_id Transaction ID.
+	 * @param  string   $note Payment note.
 	 */
 	protected function payment_complete( $order, $txn_id = '', $note = '' ) {
 		$order->add_order_note( $note );
@@ -56,8 +69,9 @@ abstract class WC_Gateway_Paypal_Response {
 
 	/**
 	 * Hold order and add note.
-	 * @param  WC_Order $order
-	 * @param  string   $reason
+	 *
+	 * @param  WC_Order $order Order object.
+	 * @param  string   $reason Reason why the payment is on hold.
 	 */
 	protected function payment_on_hold( $order, $reason = '' ) {
 		$order->update_status( 'on-hold', $reason );
diff --git a/includes/gateways/simplify-commerce/class-wc-addons-gateway-simplify-commerce.php b/includes/gateways/simplify-commerce/class-wc-addons-gateway-simplify-commerce.php
index ea3b58d0bec..f39fc002f25 100644
--- a/includes/gateways/simplify-commerce/class-wc-addons-gateway-simplify-commerce.php
+++ b/includes/gateways/simplify-commerce/class-wc-addons-gateway-simplify-commerce.php
@@ -7,12 +7,12 @@ if ( ! defined( 'ABSPATH' ) ) {
 /**
  * Simplify Commerce Gateway for subscriptions.
  *
- * @class 		WC_Addons_Gateway_Simplify_Commerce
- * @extends		WC_Gateway_Simplify_Commerce
+ * @class       WC_Addons_Gateway_Simplify_Commerce
+ * @extends     WC_Gateway_Simplify_Commerce
  * @since       2.2.0
- * @version		1.0.0
- * @package		WooCommerce/Classes/Payment
- * @author 		WooThemes
+ * @version     1.0.0
+ * @package     WooCommerce/Classes/Payment
+ * @author      WooThemes
  */
 class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 
@@ -101,12 +101,14 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 			}
 
 			// Create customer
-			$customer = Simplify_Customer::createCustomer( array(
-				'token'     => $cart_token,
-				'email'     => $order->get_billing_email(),
-				'name'      => trim( $order->get_formatted_billing_full_name() ),
-				'reference' => $order->get_id(),
-			) );
+			$customer = Simplify_Customer::createCustomer(
+				array(
+					'token'     => $cart_token,
+					'email'     => $order->get_billing_email(),
+					'name'      => trim( $order->get_formatted_billing_full_name() ),
+					'reference' => $order->get_id(),
+				)
+			);
 
 			if ( is_object( $customer ) && '' != $customer->id ) {
 				$this->save_subscription_meta( $order->get_id(), $customer->id );
@@ -149,7 +151,7 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 	/**
 	 * Store the customer and card IDs on the order and subscriptions in the order.
 	 *
-	 * @param int $order_id
+	 * @param int    $order_id
 	 * @param string $customer_id
 	 */
 	protected function save_subscription_meta( $order_id, $customer_id ) {
@@ -194,12 +196,14 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 				}
 
 				// Create customer
-				$customer = Simplify_Customer::createCustomer( array(
-					'token'     => $cart_token,
-					'email'     => $order->get_billing_email(),
-					'name'      => trim( $order->get_formatted_billing_full_name() ),
-					'reference' => $order->get_id(),
-				) );
+				$customer = Simplify_Customer::createCustomer(
+					array(
+						'token'     => $cart_token,
+						'email'     => $order->get_billing_email(),
+						'name'      => trim( $order->get_formatted_billing_full_name() ),
+						'reference' => $order->get_id(),
+					)
+				);
 
 				if ( is_object( $customer ) && '' != $customer->id ) {
 					$customer_id = wc_clean( $customer->id );
@@ -241,7 +245,6 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 					'redirect' => '',
 				);
 			}
-
 		} else {
 			return parent::process_standard_payments( $order, $cart_token );
 		}
@@ -261,12 +264,11 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 		if ( 'standard' == $this->mode && ( $this->order_contains_subscription( $order->get_id() ) || ( function_exists( 'wcs_is_subscription' ) && wcs_is_subscription( $order_id ) ) ) ) {
 			return $this->process_subscription( $order, $cart_token );
 
-		// Processing pre-order
 		} elseif ( 'standard' == $this->mode && $this->order_contains_pre_order( $order->get_id() ) ) {
+			// Processing pre-order.
 			return $this->process_pre_order( $order, $cart_token );
-
-		// Processing regular product
 		} else {
+			// Processing regular product.
 			return parent::process_payment( $order_id );
 		}
 	}
@@ -275,7 +277,7 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 	 * process_subscription_payment function.
 	 *
 	 * @param WC_order $order
-	 * @param int $amount (default: 0)
+	 * @param int      $amount (default: 0)
 	 * @uses  Simplify_BadRequestException
 	 * @return bool|WP_Error
 	 */
@@ -299,13 +301,15 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 
 		try {
 			// Charge the customer
-			$payment = Simplify_Payment::createPayment( array(
-				'amount'              => $amount * 100, // In cents.
-				'customer'            => $customer_id,
-				'description'         => sprintf( __( '%1$s - Order #%2$s', 'woocommerce' ), esc_html( get_bloginfo( 'name', 'display' ) ), $order->get_order_number() ),
-				'currency'            => strtoupper( get_woocommerce_currency() ),
-				'reference'           => $order->get_id(),
-			) );
+			$payment = Simplify_Payment::createPayment(
+				array(
+					'amount'      => $amount * 100, // In cents.
+					'customer'    => $customer_id,
+					'description' => sprintf( __( '%1$s - Order #%2$s', 'woocommerce' ), esc_html( get_bloginfo( 'name', 'display' ) ), $order->get_order_number() ),
+					'currency'    => strtoupper( get_woocommerce_currency() ),
+					'reference'   => $order->get_id(),
+				)
+			);
 
 		} catch ( Exception $e ) {
 
@@ -341,7 +345,7 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 	/**
 	 * scheduled_subscription_payment function.
 	 *
-	 * @param float $amount_to_charge The amount to charge.
+	 * @param float    $amount_to_charge The amount to charge.
 	 * @param WC_Order $renewal_order A WC_Order object created to record the renewal payment.
 	 */
 	public function scheduled_subscription_payment( $amount_to_charge, $renewal_order ) {
@@ -357,7 +361,7 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 	 * an automatic renewal payment which previously failed.
 	 *
 	 * @param WC_Subscription $subscription The subscription for which the failing payment method relates.
-	 * @param WC_Order $renewal_order The order which recorded the successful payment (to make up for the failed automatic payment).
+	 * @param WC_Order        $renewal_order The order which recorded the successful payment (to make up for the failed automatic payment).
 	 */
 	public function update_failing_payment_method( $subscription, $renewal_order ) {
 		update_post_meta( $subscription->id, '_simplify_customer_id', get_post_meta( $renewal_order->get_id(), '_simplify_customer_id', true ) );
@@ -368,7 +372,7 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 	 * manually set up automatic recurring payments for a customer via the Edit Subscription screen in Subscriptions v2.0+.
 	 *
 	 * @since 2.4
-	 * @param array $payment_meta associative array of meta data required for automatic payments
+	 * @param array           $payment_meta associative array of meta data required for automatic payments
 	 * @param WC_Subscription $subscription An instance of a subscription object
 	 * @return array
 	 */
@@ -392,7 +396,7 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 	 *
 	 * @since  2.4
 	 * @param  string $payment_method_id The ID of the payment method to validate
-	 * @param  array $payment_meta associative array of meta data required for automatic payments
+	 * @param  array  $payment_meta associative array of meta data required for automatic payments
 	 * @throws Exception
 	 */
 	public function validate_subscription_payment_meta( $payment_method_id, $payment_meta ) {
@@ -423,8 +427,8 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 	public function process_pre_order_release_payment( $order ) {
 
 		try {
-			$order_items    = $order->get_items();
-			$order_item     = array_shift( $order_items );
+			$order_items = $order->get_items();
+			$order_item  = array_shift( $order_items );
 			/* translators: 1: site name 2: product name 3: order number */
 			$pre_order_name = sprintf(
 				__( '%1$s - Pre-order for "%2$s" (Order #%3$s)', 'woocommerce' ),
@@ -440,13 +444,15 @@ class WC_Addons_Gateway_Simplify_Commerce extends WC_Gateway_Simplify_Commerce {
 			}
 
 			// Charge the customer
-			$payment = Simplify_Payment::createPayment( array(
-				'amount'              => $order->get_total() * 100, // In cents.
-				'customer'            => $customer_id,
-				'description'         => trim( substr( $pre_order_name, 0, 1024 ) ),
-				'currency'            => strtoupper( get_woocommerce_currency() ),
-				'reference'           => $order->get_id(),
-			) );
+			$payment = Simplify_Payment::createPayment(
+				array(
+					'amount'      => $order->get_total() * 100, // In cents.
+					'customer'    => $customer_id,
+					'description' => trim( substr( $pre_order_name, 0, 1024 ) ),
+					'currency'    => strtoupper( get_woocommerce_currency() ),
+					'reference'   => $order->get_id(),
+				)
+			);
 
 			if ( 'APPROVED' == $payment->paymentStatus ) {
 				// Payment complete
diff --git a/includes/gateways/simplify-commerce/class-wc-gateway-simplify-commerce.php b/includes/gateways/simplify-commerce/class-wc-gateway-simplify-commerce.php
index 1fd982ad642..0dfbd290fa7 100644
--- a/includes/gateways/simplify-commerce/class-wc-gateway-simplify-commerce.php
+++ b/includes/gateways/simplify-commerce/class-wc-gateway-simplify-commerce.php
@@ -7,12 +7,12 @@ if ( ! defined( 'ABSPATH' ) ) {
 /**
  * Simplify Commerce Gateway.
  *
- * @class 		WC_Gateway_Simplify_Commerce
- * @extends		WC_Payment_Gateway_CC
+ * @class       WC_Gateway_Simplify_Commerce
+ * @extends     WC_Payment_Gateway_CC
  * @since       2.2.0
- * @version		1.0.0
- * @package		WooCommerce/Classes/Payment
- * @author 		WooThemes
+ * @version     1.0.0
+ * @package     WooCommerce/Classes/Payment
+ * @author      WooThemes
  */
 class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 
@@ -20,12 +20,12 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 * Constructor.
 	 */
 	public function __construct() {
-		$this->id                 = 'simplify_commerce';
-		$this->method_title       = __( 'Simplify Commerce', 'woocommerce' );
-		$this->method_description = __( 'Take payments via Simplify Commerce - uses simplify.js to create card tokens and the Simplify Commerce SDK. Requires SSL when sandbox is disabled.', 'woocommerce' );
-		$this->new_method_label   = __( 'Use a new card', 'woocommerce' );
-		$this->has_fields         = true;
-		$this->supports           = array(
+		$this->id                   = 'simplify_commerce';
+		$this->method_title         = __( 'Simplify Commerce', 'woocommerce' );
+		$this->method_description   = __( 'Take payments via Simplify Commerce - uses simplify.js to create card tokens and the Simplify Commerce SDK. Requires SSL when sandbox is disabled.', 'woocommerce' );
+		$this->new_method_label     = __( 'Use a new card', 'woocommerce' );
+		$this->has_fields           = true;
+		$this->supports             = array(
 			'subscriptions',
 			'products',
 			'subscription_cancellation',
@@ -51,14 +51,14 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 		$this->init_settings();
 
 		// Get setting values
-		$this->title           = $this->get_option( 'title' );
-		$this->description     = $this->get_option( 'description' );
-		$this->enabled         = $this->get_option( 'enabled' );
-		$this->mode            = $this->get_option( 'mode', 'standard' );
-		$this->modal_color     = $this->get_option( 'modal_color', '#a46497' );
-		$this->sandbox         = $this->get_option( 'sandbox' );
-		$this->public_key      = ( 'no' === $this->sandbox ) ? $this->get_option( 'public_key' ) : $this->get_option( 'sandbox_public_key' );
-		$this->private_key     = ( 'no' === $this->sandbox ) ? $this->get_option( 'private_key' ) : $this->get_option( 'sandbox_private_key' );
+		$this->title       = $this->get_option( 'title' );
+		$this->description = $this->get_option( 'description' );
+		$this->enabled     = $this->get_option( 'enabled' );
+		$this->mode        = $this->get_option( 'mode', 'standard' );
+		$this->modal_color = $this->get_option( 'modal_color', '#a46497' );
+		$this->sandbox     = $this->get_option( 'sandbox' );
+		$this->public_key  = ( 'no' === $this->sandbox ) ? $this->get_option( 'public_key' ) : $this->get_option( 'sandbox_public_key' );
+		$this->private_key = ( 'no' === $this->sandbox ) ? $this->get_option( 'private_key' ) : $this->get_option( 'sandbox_private_key' );
 
 		$this->init_simplify_sdk();
 
@@ -74,7 +74,7 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 */
 	protected function init_simplify_sdk() {
 		// Include lib
-		require_once( dirname( __FILE__ ) . '/includes/Simplify.php' );
+		require_once dirname( __FILE__ ) . '/includes/Simplify.php';
 
 		Simplify::$publicKey  = $this->public_key;
 		Simplify::$privateKey = $this->private_key;
@@ -186,28 +186,28 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 */
 	public function init_form_fields() {
 		$this->form_fields = array(
-			'enabled' => array(
+			'enabled'             => array(
 				'title'       => __( 'Enable/Disable', 'woocommerce' ),
 				'label'       => __( 'Enable Simplify Commerce', 'woocommerce' ),
 				'type'        => 'checkbox',
 				'description' => '',
 				'default'     => 'no',
 			),
-			'title' => array(
+			'title'               => array(
 				'title'       => __( 'Title', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'This controls the title which the user sees during checkout.', 'woocommerce' ),
 				'default'     => __( 'Credit card', 'woocommerce' ),
 				'desc_tip'    => true,
 			),
-			'description' => array(
+			'description'         => array(
 				'title'       => __( 'Description', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'This controls the description which the user sees during checkout.', 'woocommerce' ),
 				'default'     => 'Pay with your credit card via Simplify Commerce by MasterCard.',
 				'desc_tip'    => true,
 			),
-			'mode' => array(
+			'mode'                => array(
 				'title'       => __( 'Payment mode', 'woocommerce' ),
 				'label'       => __( 'Enable Hosted Payments', 'woocommerce' ),
 				'type'        => 'select',
@@ -218,21 +218,21 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 					'hosted'   => __( 'Hosted Payments', 'woocommerce' ),
 				),
 			),
-			'modal_color' => array(
+			'modal_color'         => array(
 				'title'       => __( 'Modal color', 'woocommerce' ),
 				'type'        => 'color',
 				'description' => __( 'Set the color of the buttons and titles on the modal dialog.', 'woocommerce' ),
 				'default'     => '#a46497',
 				'desc_tip'    => true,
 			),
-			'sandbox' => array(
+			'sandbox'             => array(
 				'title'       => __( 'Sandbox', 'woocommerce' ),
 				'label'       => __( 'Enable sandbox mode', 'woocommerce' ),
 				'type'        => 'checkbox',
 				'description' => __( 'Place the payment gateway in sandbox mode using sandbox API keys (real payments will not be taken).', 'woocommerce' ),
 				'default'     => 'yes',
 			),
-			'sandbox_public_key' => array(
+			'sandbox_public_key'  => array(
 				'title'       => __( 'Sandbox public key', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'Get your API keys from your Simplify account: Settings > API Keys.', 'woocommerce' ),
@@ -246,14 +246,14 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 				'default'     => '',
 				'desc_tip'    => true,
 			),
-			'public_key' => array(
+			'public_key'          => array(
 				'title'       => __( 'Public key', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'Get your API keys from your Simplify account: Settings > API Keys.', 'woocommerce' ),
 				'default'     => '',
 				'desc_tip'    => true,
 			),
-			'private_key' => array(
+			'private_key'         => array(
 				'title'       => __( 'Private key', 'woocommerce' ),
 				'type'        => 'text',
 				'description' => __( 'Get your API keys from your Simplify account: Settings > API Keys.', 'woocommerce' ),
@@ -301,15 +301,17 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 
 		wp_enqueue_script( 'simplify-commerce', 'https://www.simplify.com/commerce/v1/simplify.js', array( 'jquery' ), WC_VERSION, true );
 		wp_enqueue_script( 'wc-simplify-commerce', WC()->plugin_url() . '/includes/gateways/simplify-commerce/assets/js/simplify-commerce.js', array( 'simplify-commerce', 'wc-credit-card-form' ), WC_VERSION, true );
-		wp_localize_script( 'wc-simplify-commerce', 'Simplify_commerce_params', array(
-			'key'           => $this->public_key,
-			'card.number'   => __( 'Card number', 'woocommerce' ),
-			'card.expMonth' => __( 'Expiry month', 'woocommerce' ),
-			'card.expYear'  => __( 'Expiry year', 'woocommerce' ),
-			'is_invalid'    => __( 'is invalid', 'woocommerce' ),
-			'mode'          => $this->mode,
-			'is_ssl'        => is_ssl(),
-		) );
+		wp_localize_script(
+			'wc-simplify-commerce', 'Simplify_commerce_params', array(
+				'key'           => $this->public_key,
+				'card.number'   => __( 'Card number', 'woocommerce' ),
+				'card.expMonth' => __( 'Expiry month', 'woocommerce' ),
+				'card.expYear'  => __( 'Expiry year', 'woocommerce' ),
+				'is_invalid'    => __( 'is invalid', 'woocommerce' ),
+				'mode'          => $this->mode,
+				'is_ssl'        => is_ssl(),
+			)
+		);
 	}
 
 	public function add_payment_method() {
@@ -342,33 +344,35 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 * Actually saves a customer token to the database.
 	 *
 	 * @param  WC_Payment_Token $customer_token Payment Token
-	 * @param  string $cart_token CC Token
-	 * @param  array $customer_info 'email', 'name'
+	 * @param  string           $cart_token CC Token
+	 * @param  array            $customer_info 'email', 'name'
 	 *
 	 * @return null|WC_Payment_Token|WC_Payment_Token_CC
 	 */
 	public function save_token( $customer_token, $cart_token, $customer_info ) {
 		if ( ! is_null( $customer_token ) ) {
 			$customer = Simplify_Customer::findCustomer( $customer_token->get_token() );
-			$updates = array( 'token' => $cart_token );
+			$updates  = array( 'token' => $cart_token );
 			$customer->setAll( $updates );
 			$customer->updateCustomer();
 			$customer = Simplify_Customer::findCustomer( $customer_token->get_token() ); // get updated customer with new set card
-			$token = $customer_token;
+			$token    = $customer_token;
 		} else {
-			$customer = Simplify_Customer::createCustomer( array(
-				'token'     => $cart_token,
-				'email'     => $customer_info['email'],
-				'name'      => $customer_info['name'],
-			) );
-			$token = new WC_Payment_Token_CC();
+			$customer = Simplify_Customer::createCustomer(
+				array(
+					'token' => $cart_token,
+					'email' => $customer_info['email'],
+					'name'  => $customer_info['name'],
+				)
+			);
+			$token    = new WC_Payment_Token_CC();
 			$token->set_token( $customer->id );
 		}
 
 		// If we were able to create an save our card, save the data on our side too
 		if ( is_object( $customer ) && '' != $customer->id ) {
 			$customer_properties = $customer->getProperties();
-			$card = $customer_properties['card'];
+			$card                = $customer_properties['card'];
 			$token->set_gateway_id( $this->id );
 			$token->set_card_type( strtolower( $card->type ) );
 			$token->set_last4( $card->last4 );
@@ -388,9 +392,9 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	/**
 	 * Process customer: updating or creating a new customer/saved CC
 	 *
-	 * @param  WC_Order           $order          Order object
-	 * @param  WC_Payment_Token   $customer_token Payment Token
-	 * @param  string             $cart_token     CC Token
+	 * @param  WC_Order         $order          Order object
+	 * @param  WC_Payment_Token $customer_token Payment Token
+	 * @param  string           $cart_token     CC Token
 	 */
 	protected function process_customer( $order, $customer_token = null, $cart_token = '' ) {
 		// Are we saving a new payment method?
@@ -399,7 +403,7 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 				'email' => $order->get_billing_email(),
 				'name'  => trim( $order->get_formatted_billing_full_name() ),
 			);
-			$token = $this->save_token( $customer_token, $cart_token, $customer_info );
+			$token         = $this->save_token( $customer_token, $cart_token, $customer_info );
 			if ( ! is_null( $token ) ) {
 				$order->add_payment_token( $token );
 			}
@@ -410,8 +414,8 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 * Process standard payments.
 	 *
 	 * @param  WC_Order $order
-	 * @param  string $cart_token
-	 * @param string $customer_token
+	 * @param  string   $cart_token
+	 * @param string   $customer_token
 	 *
 	 * @return array
 	 * @uses   Simplify_ApiException
@@ -489,8 +493,8 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 * do payment function.
 	 *
 	 * @param WC_order $order
-	 * @param int $amount (default: 0)
-	 * @param array $token
+	 * @param int      $amount (default: 0)
+	 * @param array    $token
 	 *
 	 * @return bool|WP_Error
 	 * @uses  Simplify_BadRequestException
@@ -503,13 +507,13 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 		try {
 			// Charge the customer
 			$data = array(
-				'amount'              => $amount * 100, // In cents.
-				'description'         => sprintf( __( '%1$s - Order #%2$s', 'woocommerce' ), esc_html( get_bloginfo( 'name', 'display' ) ), $order->get_order_number() ),
-				'currency'            => strtoupper( get_woocommerce_currency() ),
-				'reference'           => $order->get_id(),
+				'amount'      => $amount * 100, // In cents.
+				'description' => sprintf( __( '%1$s - Order #%2$s', 'woocommerce' ), esc_html( get_bloginfo( 'name', 'display' ) ), $order->get_order_number() ),
+				'currency'    => strtoupper( get_woocommerce_currency() ),
+				'reference'   => $order->get_id(),
 			);
 
-			$data = array_merge( $data, $token );
+			$data    = array_merge( $data, $token );
 			$payment = Simplify_Payment::createPayment( $data );
 
 		} catch ( Exception $e ) {
@@ -557,7 +561,7 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	}
 
 	protected function get_users_token() {
-		$customer_token  = null;
+		$customer_token = null;
 		if ( is_user_logged_in() ) {
 			$tokens = WC_Payment_Tokens::get_customer_tokens( get_current_user_id() );
 			foreach ( $tokens as $token ) {
@@ -615,22 +619,24 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 * @return array
 	 */
 	protected function get_hosted_payments_args( $order ) {
-		$args = apply_filters( 'woocommerce_simplify_commerce_hosted_args', array(
-			'sc-key'          => $this->public_key,
-			'amount'          => $order->get_total() * 100,
-			'reference'       => $order->get_id(),
-			'name'            => esc_html( get_bloginfo( 'name', 'display' ) ),
-			'description'     => sprintf( __( 'Order #%s', 'woocommerce' ), $order->get_order_number() ),
-			'receipt'         => 'false',
-			'color'           => $this->modal_color,
-			'redirect-url'    => WC()->api_request_url( 'WC_Gateway_Simplify_Commerce' ),
-			'address'         => $order->get_billing_address_1() . ' ' . $order->get_billing_address_2(),
-			'address-city'    => $order->get_billing_city(),
-			'address-state'   => $order->get_billing_state(),
-			'address-zip'     => $order->get_billing_postcode(),
-			'address-country' => $order->get_billing_country(),
-			'operation'       => 'create.token',
-		), $order->get_id() );
+		$args = apply_filters(
+			'woocommerce_simplify_commerce_hosted_args', array(
+				'sc-key'          => $this->public_key,
+				'amount'          => $order->get_total() * 100,
+				'reference'       => $order->get_id(),
+				'name'            => esc_html( get_bloginfo( 'name', 'display' ) ),
+				'description'     => sprintf( __( 'Order #%s', 'woocommerce' ), $order->get_order_number() ),
+				'receipt'         => 'false',
+				'color'           => $this->modal_color,
+				'redirect-url'    => WC()->api_request_url( 'WC_Gateway_Simplify_Commerce' ),
+				'address'         => $order->get_billing_address_1() . ' ' . $order->get_billing_address_2(),
+				'address-city'    => $order->get_billing_city(),
+				'address-state'   => $order->get_billing_state(),
+				'address-zip'     => $order->get_billing_postcode(),
+				'address-country' => $order->get_billing_country(),
+				'operation'       => 'create.token',
+			), $order->get_id()
+		);
 
 		return $args;
 	}
@@ -715,8 +721,8 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 	 * Process refunds.
 	 * WooCommerce 2.2 or later.
 	 *
-	 * @param  int $order_id
-	 * @param  float $amount
+	 * @param  int    $order_id
+	 * @param  float  $amount
 	 * @param  string $reason
 	 * @uses   Simplify_ApiException
 	 * @uses   Simplify_BadRequestException
@@ -726,12 +732,14 @@ class WC_Gateway_Simplify_Commerce extends WC_Payment_Gateway_CC {
 		try {
 			$payment_id = get_post_meta( $order_id, '_transaction_id', true );
 
-			$refund = Simplify_Refund::createRefund( array(
-				'amount'    => $amount * 100, // In cents.
-				'payment'   => $payment_id,
-				'reason'    => $reason,
-				'reference' => $order_id,
-			) );
+			$refund = Simplify_Refund::createRefund(
+				array(
+					'amount'    => $amount * 100, // In cents.
+					'payment'   => $payment_id,
+					'reason'    => $reason,
+					'reference' => $order_id,
+				)
+			);
 
 			if ( 'APPROVED' == $refund->paymentStatus ) {
 				return true;