fix php 8.x

Author: NikoGrano

Protocols/EPP/eppResponses/eppResponse.php

@@ -79,7 +79,7 @@ class eppResponse extends \DOMDocument {
     /*
      * @var array of supported versions
      */
-    public $version;
+    public ?string $version;
 
     public $originalrequest;
     /**
@@ -123,9 +123,9 @@ public function dumpContents() {
      */
     public function Success() {
         $resultcode = $this->getResultCode();
-        $success = ($resultcode{0} == '1');
+        $success = ($resultcode[0] == '1');
         if (!$success) {
-            switch ($resultcode{1}) {
+            switch ($resultcode[1]) {
                 case '0':
                     $this->setProblemtype('syntax');
                     break;