Initial commit
diff --git a/includes/migrations/class-allowed-payment-request-button-types-update.php b/includes/migrations/class-allowed-payment-request-button-types-update.php
new file mode 100644
index 0000000..cad13a9
--- /dev/null
+++ b/includes/migrations/class-allowed-payment-request-button-types-update.php
@@ -0,0 +1,81 @@
+<?php
+/**
+ * Class Allowed_Payment_Request_Button_Types_Update
+ */
+
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Class Allowed_Payment_Request_Button_Types_Update
+ *
+ * Remaps deprecated payment request button types to fallback values.
+ *
+ * @since 5.6.0
+ */
+class Allowed_Payment_Request_Button_Types_Update {
+	/**
+	 * Allowed_Payment_Request_Button_Types_Update constructor.
+	 */
+	public function __construct() {
+		add_action( 'woocommerce_stripe_updated', [ $this, 'maybe_migrate' ] );
+	}
+
+	/**
+	 * Only execute the migration if not applied yet.
+	 */
+	public function maybe_migrate() {
+		// not compatible with older WC versions, due to the missing `update_option` method on the gateway class
+		if ( version_compare( WC_VERSION, '3.4.0', '<' ) ) {
+			return;
+		}
+
+		$stripe_gateway = $this->get_gateway();
+
+		// "custom" or "branded" are no longer valid values for the button type - map them to new ones
+		$button_type = $stripe_gateway->get_option( 'payment_request_button_type' );
+		if ( in_array( $button_type, [ 'branded', 'custom' ], true ) ) {
+			$branded_type = $stripe_gateway->get_option( 'payment_request_button_branded_type' );
+			$stripe_gateway->update_option(
+				'payment_request_button_type',
+				$this->map_button_type( $button_type, $branded_type )
+			);
+		}
+	}
+
+	/**
+	 * Maps deprecated button types to fallback values.
+	 *
+	 * @param mixed $button_type "payment_request_button_type" value.
+	 * @param mixed $branded_type "payment_request_button_branded_type" value.
+	 *
+	 * @return mixed
+	 */
+	private function map_button_type( $button_type, $branded_type ) {
+		// "branded" with "logo only" => "default" (same result)
+		if ( 'branded' === $button_type && 'short' === $branded_type ) {
+			return 'default';
+		}
+
+		// "branded" with anything else (which would be "long"/"Text and logo") => "buy"
+		if ( 'branded' === $button_type ) {
+			return 'buy';
+		}
+
+		// "custom" is no longer valid => "default"
+		if ( 'custom' === $button_type ) {
+			return 'buy';
+		}
+
+		// anything else is good
+		return $button_type;
+	}
+
+	/**
+	 * Returns the main Stripe payment gateways.
+	 *
+	 * @return WC_Stripe_Payment_Gateway
+	 */
+	public function get_gateway() {
+		return woocommerce_gateway_stripe()->get_main_stripe_gateway();
+	}
+}