Update to Drupal 8.1.0. For more information, see https://www.drupal.org/drupal-8.1.0-release-notes

vendor/symfony/validator/Constraints/Currency.php

@@ -18,8 +18,15 @@ use Symfony\Component\Validator\Constraint;
  * @Target({"PROPERTY", "METHOD", "ANNOTATION"})
  *
  * @author Miha Vrhovnik <miha.vrhovnik@pagein.si>
+ * @author Bernhard Schussek <bschussek@gmail.com>
  */
 class Currency extends Constraint
 {
+    const NO_SUCH_CURRENCY_ERROR = '69945ac1-2db4-405f-bec7-d2772f73df52';
+
+    protected static $errorNames = array(
+        self::NO_SUCH_CURRENCY_ERROR => 'NO_SUCH_CURRENCY_ERROR',
+    );
+
     public $message = 'This value is not a valid currency.';
 }