diff --git a/src/PhpSpreadsheet/Reader/Html.php b/src/PhpSpreadsheet/Reader/Html.php
index 4edf3cf8..3d859e15 100644
--- a/src/PhpSpreadsheet/Reader/Html.php
+++ b/src/PhpSpreadsheet/Reader/Html.php
@@ -632,16 +632,6 @@ class Html extends BaseReader
         }
     }
 
-    /**
-     * Make sure mb_convert_encoding returns string.
-     *
-     * @param mixed $result
-     */
-    private static function ensureString($result): string
-    {
-        return is_string($result) ? $result : '';
-    }
-
     /**
      * Loads PhpSpreadsheet from file into PhpSpreadsheet instance.
      *
@@ -660,8 +650,8 @@ class Html extends BaseReader
         $dom = new DOMDocument();
         // Reload the HTML file into the DOM object
         try {
-            $convert = mb_convert_encoding($this->securityScanner->scanFile($filename), 'HTML-ENTITIES', 'UTF-8');
-            $loaded = $dom->loadHTML(self::ensureString($convert));
+            $convert = $this->securityScanner->scanFile($filename);
+            $loaded = $dom->loadHTML($convert);
         } catch (Throwable $e) {
             $loaded = false;
         }
@@ -683,8 +673,8 @@ class Html extends BaseReader
         $dom = new DOMDocument();
         //    Reload the HTML file into the DOM object
         try {
-            $convert = mb_convert_encoding($this->securityScanner->scan($content), 'HTML-ENTITIES', 'UTF-8');
-            $loaded = $dom->loadHTML(self::ensureString($convert));
+            $convert = $this->securityScanner->scan($content);
+            $loaded = $dom->loadHTML($convert);
         } catch (Throwable $e) {
             $loaded = false;
         }
diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index 8562339b..52df94e4 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -414,7 +414,7 @@ class Xlsx extends BaseReader
         [$workbookBasename, $xmlNamespaceBase] = $this->getWorkbookBaseName();
         $drawingNS = self::REL_TO_DRAWING[$xmlNamespaceBase] ?? Namespaces::DRAWINGML;
         $chartNS = self::REL_TO_CHART[$xmlNamespaceBase] ?? Namespaces::CHART;
-        $wbRels = $this->loadZip("xl/_rels/${workbookBasename}.rels", Namespaces::RELATIONSHIPS);
+        $wbRels = $this->loadZip("xl/_rels/{$workbookBasename}.rels", Namespaces::RELATIONSHIPS);
         $theme = null;
         $this->styleReader = new Styles();
         foreach ($wbRels->Relationship as $relx) {
@@ -1849,11 +1849,6 @@ class Xlsx extends BaseReader
 
     private static function dirAdd($base, $add): string
     {
-        $add = "$add";
-        if (substr($add, 0, 4) === '/xl/') {
-            $add = substr($add, 4);
-        }
-
         return (string) preg_replace('~[^/]+/\.\./~', '', dirname($base) . "/$add");
     }